Three people involved in trafficking women to the UK where they were forced into sex work have been jailed for a total of 27 years today (23 January 2026) following a complex and painstaking investigation by specialist detectives.
They were brought to justice as a result of a lengthy enquiry by officers from West Yorkshire Police’s Modern Slavery and Human Trafficking Team, which is part of the force’s Programme Precision initiative that tackles serious and organised crime.
Detectives launched Operation Laggenend in July 2016 after West Yorkshire Police received information in an anonymous letter, which was later established to be from one of the victims.
Polish nationals Wieslaw Michniewicz and Aleksandra Timoszek, who were married at the time, were identified as key suspects in the investigation, which focused on offences that took place between December 2015 and September 2016.
The pair, who lived at an address in Willow Avenue, Burley, Leeds, targeted vulnerable women, predominantly living in Poland, and offered them legitimate work in the UK.
The victims were told they had jobs as childminders or in local bars or shops. Others believed they were travelling to the UK to start a romantic relationship with Michniewicz.
Their travel was paid for and they were offered accommodation at the couple’s address in Willow Avenue.
When the victims arrived in the UK, they were told they now had a debt to pay off and were forced into sex work. Threats were made to the victims and against their families back in Poland, including threats to shame them in their communities as sex workers.
The investigation showed how the women had been transported by the couple on a daily basis to massage clubs, including Winstons Health and Leisure, in Dewsbury Road, Beeston, and Diplomat Massage Ltd, in Attercliffe Road, Sheffield.
The women were forced to work up to 20 hours a day, seven days a week providing sexual services at the venues. All the money they earned was then handed directly to Michniewicz and Timoszek.
Enquiries by officers showed that the pair had been assisted by Michniewicz’s cousin Mariusz Seretny, who was living at Grange Close, Hunslet. Evidence linked him to travel bookings, advertisements on sex work websites and money transfers out of the UK. His wife Marta Seretny was also found to have had a supporting role in the prostitution of the women.
Officers arrested Michniewicz and Timoszek at their home address on 14 September 2016, on suspicion of offences relating to modern slavery.
Several women were found at the address and safeguarded by police. Items recovered from the property included £16,000 in cash, mobile phones and handwritten ledgers detailing the earnings and debt for each of the women under the couple’s control.
Three luxury sports cars – a Porsche Panamera, a Porsche Carrera and an Audi R8 – were also seized from the couple.
Mariusz and Marta Seretney were also subsequently arrested, and the four – who had all been in the UK legitimately at the time off the offences – were later released on bail while enquiries continued.
In a complex investigation spanning several years, officers were able to establish a pattern of offending behaviour from the initial contact with victims to the control and exploitation of them.
The investigation identified 14 victims, aged between 17 and 31, who had been targeted. Two women had been considered unsuitable on arrival in the UK and were sent back to Poland, and another had become suspicious and refused to travel to the UK. The youngest was brought to the UK while only 17 and was put to work in a brothel the day after her eighteenth birthday.
Key evidence included social media communication, with more than 1,000 pages of content secured and translated from Polish into English; travel bookings and documents for flights and ferry crossings that brought the victims to the UK; mobile phones with thousands of messages, images and videos recovered, including the victims’ passport details; analysis of handwritten ledgers recovered at the address showing that prostitution of the 11 victims had generated about £170,000 over the period of the offences, with details of the sizeable debts each victim faced; receipts from the Willow Avenue address showing large sums of money being transferred out of the country; and CCTV footage from the house showing the victims being driven off by Michniewicz and Timoszek on a daily basis and the pair depositing sums of cash in the safe on their return.
Throughout the investigation, detectives maintained contact with the victims, many of whom returned to Poland following the arrests of Michniewicz and Timoszek.
The investigation team sought the assistance of the Polish authorities and, through a joint investigation team facilitated by Europol, were able to safeguard and support the victims in Poland and use specially trained officers to secure their evidence.
Following detailed consultation with the Crown Prosecution Service, the decision was made on 27 February 2023, to charge the four with modern slavery and controlling prostitution offences.
Both Michniewicz and Timoszek had fled the country in the meantime, but the pair were traced by officers and extradited back to the UK and remanded in custody until their trial, which began at Leeds Crown Court in November 2025.
Special measures were put in place for the trial to assist those who gave evidence at court. These included a live video link from Poland, video recorded interviews being used as evidence in chief and victims being able to give evidence in private.
On 18 December 2025, the jury returned unanimous guilty verdicts against all four defendants.
Michniewicz, Timoszek and Mariusz Seretny were each convicted of conspiracy to arrange or facilitate the travel of another person with a view to exploitation; conspiracy to incite another person to become a prostitute for gain; conspiracy to control prostitution for gain; and two counts of controlling prostitution for gain in relation to two individual victims.
Marta Seretny was found guilty of one count of conspiracy to control prostitution for gain.
Today, they were sentenced for those offences.
Michniewicz, aged 53, was sentenced to 15 years’ imprisonment for the modern slavery offence with a six-year concurrent term for the prostitution offences; Timoszek, aged 32, was given a seven-and-a-half-year jail term for the modern slavery offence with three years concurrent for the other matters; and Mariusz Seretny, aged 45, was jailed for five years for the modern slavery offence with a one-year concurrent term for the offences.
Slavery and Trafficking Prevention Orders, under the Modern Slavery Act 2015, which place restrictions on convicted offenders to protect the public from future harm, are being sought against the three, and proceedings under the Proceeds of Crime Act 2002 are currently ongoing in relation to the assets seized.
Marta Seretny, aged 41, was given a 12-month community order and ordered to complete 80 hours of unpaid work.
Senior Investigating Officer, Detective Superintendent Helen Steele said:
“These four were involved in an organised criminal enterprise that cruelly targeted vulnerable women and preyed on their hopes of a better life with legitimate employment in the UK.
“Instead, the victims found themselves being controlled and forced into sex work where they were relentlessly exploited and treated purely as commodities to make money from.
“The victims have each suffered harrowing experiences and have been left understandably traumatised by the ordeals they were put through. We hope that it will help them in some way to know that those responsible have now been brought to justice.
“Modern slavery offences are truly abhorrent, and we remain absolutely committed to doing everything we can to target those involved. This is a crime that is often hidden in plain sight, and we would urge members of the public to report any suspicions they have that this type of exploitation is taking place to us immediately.”
Information can be reported to West Yorkshire Police via 101, to the Modern Slavery Helpline anonymously on 0800 121 700 or online at www.modernslaveryhelpline.org or to the independent charity Crimestoppers on 0800 555 111.
This post is based on a press release issued by West Yorkshire Police
Main photo L-R: Wieslaw Michniewicz, Aleksandra Timoszek and Mariusz Seretny
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