The fourth suspect in the Pattaya murder of a German businessman claims he was forced to help his co-accused and fears for his life if he is placed in the same prison as the alleged mastermind of the crime, his family says.

Shahrukh Karim Uddin, 27, a Pakistani with Thai nationality, insisted he did not kill Hans-Peter Mack, whose dismembered body was found in a freezer at a rented house in Pattaya.

He denied all charges and said he would give his statement in court.

Police on Friday took him to the Pattaya Provincial Court to seek approval to detain him.

On seeing reporters, he shouted out, “I’m afraid, I didn’t do it and I didn’t kill.”

Mr Uddin was arrested at a hotel in Kanchanaburi on Wednesday afternoon while preparing to flee across the border to Myanmar, said police.

Olaf Thorsten Brinkmann, 52, the alleged mastermind of the crime, was arrested earlier along with two German women: Petra Christl Grundgreif, 54; and Nicole Frevel, 52. All three denied any involvement.

Surveillance camera video showed Mr Uddin sitting in the bed of a pickup truck next to a freezer containing the dismembered body of Mack, 62. The suspect was also seen in CCTV video with Mr Brinkmann as they bought some gear at a fishing supplies shop in Chon Buri.

Police seized a speedboat belonging to Mr Brinkmann from a house in Pattaya on Wednesday night.

Investigators believe he and Mr Uddin were planning to dump Mack’s body in the sea. However, the body of the victim was found at a rented house in tambon Nong Prue on Monday night — six days after the German went missing.

Mr Uddin claimed he had been forced by Mr Brinkmann to help him.

His family was worried about Mr Uddin’s safety if he is sent to the same prison as Mr Brinkmann. They fear he might be silenced, said the brother.

A source said Mr Uddin had told police that Ms Grundgreif had asked him to open a pool villa to hold a party for a VIP guest on July 4. On that day, Mr Brinkmann and Ms Grundgreif and Mack arrived and went inside. Mr Uddin said he had been told to wait outside.

After waiting for more than three hours, Mr Uddin decided to go inside the villa. On opening the door, he found Mack lying unconscious on sofa. He then asked the two Germans what they were doing. Mr Brinkmann pushed him against the wall and used a gun to threaten him.

The German man allegedly threatened to abduct his younger sister and his wife if he did not cooperate. Mr Uddin also alleged that Mr Brinkmann had threatened to kill his parents in Phuket if he betrayed the gang.