Police have arrested two more people in connection with the suspected murder of Co Down father-of-four.
William McCormick, known as Pat, was last seen in Comber on Thursday.
The 55-year-old has not made contact with his family since.
The PSNI launched a murder inquiry and have issued CCTV footage of his last known movements in a new appeal for information.
A 39-year-old man and a 20-year-old man were detained on Wednesday night on suspicion of assisting offenders and perverting the course of justice. They were taken to Musgrave police station for questioning.
A 26-year-old man and a 20-year-old woman who were rearrested on suspicion of murder on Monday were released from police custody on Wednesday evening. They had previously been arrested on suspicion of kidnapping.
Detective Chief Inspector Pete Montgomery said Mr McCormick was last seen walking along Castle Street in Comber.
"I know that Pat left his parent's house in Ballynahinch on Thursday, May 30th just after 9pm," he said.
“In the CCTV, Pat can be seen driving his car in Castle Street, Comber, at around 10.30pm — it’s a black Citroen C4, registration BSZ 7103.
“I know that Pat then parked his car on High Street, opposite McBride’s pub, where it remained until it was recovered by police.
“In the footage, Pat can be seen walking down Castle Street at around 10.45pm, where he goes under an archway that leads to some flats.
“This is the last sighting that I have.”
Six days on from Mr McCormick’s disappearance, Mr Montgomery said his family deserve to know what happened to him.
“I have met with Pat’s wife and parents and they are devastated.
“His mother and father are in their 80s and they deserve to get his body back.
“Members of the local community could have information that could be key to giving Pat’s family some answers.” – PA