Two further arrests have been made in connection with the 1984 murder of Anthony Littler in north London.
Mr Littler was found with head injuries in an alleyway known as The Causeway, near East Finchley Tube station at 12.15am on May 1 1984.
Mr Littler, an executive officer at Customs and Excise, was single and lived a short distance from the station.
Police believe he was murdered in a random attack.
One man, aged 56, and another aged 57 have been arrested on suspicion of murder and remain in custody, the force said.
In December, the Metropolitan Police launched an appeal for information surrounding his death, leading to the arrest of a 58-year-old man on suspicion of murder.
Later that month, a 54-year-old man was also arrested on suspicion of murder.
They have both been re-bailed to a date in late April.
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