A 15-year-old girl and a 41-year-old man were being questioned today by detectives investigating the deaths of a man and a woman.
Both suspects were arrested yesterday following the discovery of two bodies at separate flats in Ipswich, Suffolk, police said.
Officers said the dead woman was found at a flat in Victoria Street early on Sunday.
The dead man was found at a flat in Limerick Close, about two miles away, early yesterday.
A police spokeswoman said both suspects had been arrested on suspicion of murder.
But experts were not sure why the two people had died and officers were treating the deaths as "suspicious", she added.
Both the dead man and the dead woman are thought to have been in their 40s.
Neighbours named the dead woman as Rose Hunt and said she lived alone.
Unemployed Paul Devereux, 45, who lives in Limerick Close, said a man and a teenage girl had been staying at a neighbouring flat for the past few days.
They appeared to be "in a relationship", he said.
Mr Devereux said a £25 closed circuit television camera he had fitted to the side of his flat had recorded activity in the early hours.
He had handed footage to police, he said.