Kamil Zydek, 34, of no fixed address, had denied murdering Marcin Stolarek whose body was found by a service engineer at the Chain Bridge Road pumping station in Wyberton, near Boston in January 2020.
A jury at Lincoln Crown Court today (Thursday) failed to reach a verdict on the murder charge after deliberating for more than 17 hours.
Zydek was found guilty by the jury of a second charge of conspiracy to pervert the course of public justice relating to Mr Stolarek's disappearance.
He will now face a retrial next year and will be sentenced for perverting the course of justice at the end of that trial.
Judge Simon Hirst told Zydek: "The jury have found you guilty of perverting the course of justice. They could not decide on the count of murder. The prosecution wish to have a retrial."
The prosecution alleged Zydek was part of a team of three men who planned the murder of Mr Stolarek, 41, and then the disposal of his body.
Two other men, Lukasz Ferenc and Adam Kaminski, have already been convicted of Mr Stolarek's murder and are serving life sentences.
The prosecution claimed that Zydek was working in a team with Ferenc and Kaminski when Mr Stolarek was attacked and disposed of during the early hours of November 28, 2019.
Gordon Aspden KC, prosecuting, told the jury Mr Stolarek was tied up and savagely beaten at the home of Kaminski in Union Court, Boston.
Mr Aspden alleged Mr Stolarek was then put in the boot of a Vauxhall Astra driven by Artur Klosowski, with Ferenc and Zydek helping to dispose of his dead or dying body.
However, in the witness box, Zydek insisted he asked for Mr Stolarek to be taken to hospital and said he remained in the car when his dead or dying body was dumped.
Giving evidence via a Polish interpreter, Zydek admitted he was a passenger in Klosowski's car when it was driven eastbound across Boston's Sluice Bridge towards Union Court at 3.46am on November 28, 2019.
ANPR cameras showed it travelling back in the opposite direction 15 minutes later.
Answering questions from defence barrister, Alisdair Williams KC, Zydek said the vehicle was directed to the back of the house by Adam Kaminski.
The jury heard Zydek had been in contact with Ferenc by text message and phone after crossing over Sluice Bridge.
Zydek was asked by Mr Williams: "What was going on?"
He replied: "I don't know, I don't remember," adding that he must have been telling him that they were on their way.
Once at Union Court, Zydek said he got out of the car and went to the back door.
"I was stood in the doorway when I saw what they were doing," Zydek told the jury.
Zydek said he didn't know what to do, and went back and forth to the car.
"I went in, I went out," Zydek added. "I didn't even see his (Marcin's) face."
Zydek said Klosowski then got back into the car.
"When Artur was getting back in the car, Adam and Lukasz were putting Marcin in the boot," Zydek told the jury.
"I didn't know what to think. I was scared. Everything was happening so quickly."
Zydek said Ferenc then also got in the vehicle.
"I said to Artur to go to a hospital, but Lukasz disagreed," Zydek insisted.
"I said to Artur that if you can't go to the hospital then leave him in front of the hospital, but Lukasz got angry and told me to 'shut up.' "
Zydek was then asked what condition he thought Mr Stolarek was in?
He replied: "I don't know, I have no idea."
Zydek said Ferenc then gave Artur directions where to drive.
Under cross-examination from Mr Aspden, Zydek said he remained in the car when Mr Stolarek was removed from the boot.
Zydek admitted he met with Ferenc in December 2019 and said he carried on with his normal life as he thought Mr Stolarek would have been strong enough to get away.
The jury heard Klosowski left England in January 2020, driving the Astra car to Holyhead in Wales before taking a ferry to the Republic of Ireland.
Zydek was arrested by Dutch police earlier this year and extradited to the UK to stand trial.