Neighbours have told of their sadness at the deaths of a “lovely” young mother and her toddler son.
The pair, named by police as 19-year-old Kia Russell and her two-year-old son Kamari, were found at an address in Swinburne Road, Ipswich, on Wednesday and treated by paramedics but died at the scene.
Suffolk Police said initial inquiries indicate that there is “no third-party involvement”.
Home Office post-mortem examinations are due to take place on 12 March.
A police officer stood outside the semi-detached house on Thursday morning, with floral tributes laid beside the garden gate.
Officers said the victims’ next of kin have been informed.
Former neighbour Lisa Horne, 39, described Russell as “lovely”, adding that she believed she was in her late teens.
“She always kept herself to herself,” she said, after placing flowers outside the house.
“She was in the garden with her son, or when we were doing the car she was there with hers.
“She always said ‘Morning’ or ‘Hello’. It’s a bit of a shock.”
She continued: “Every time we were out here she was polite.
“We were here for about a year-and-a-half before we moved at Christmas. She was lovely. She never had any issues and was quiet.
“I just feel at a loss, at such a young age for both of them, no life at all really.”
Another woman who left a bouquet for the young mum said: “She was just a lovely girl. Just a lovely, bubbly girl, always giggling.”
Her friend, whose sister was friends with Russell at school, said she was “always happy”, adding: “She was a good mum, a very good mum.”
The Reverend Mary Sokanovic, priest in charge of the parish of Whitton with Thurleston and Akenham, went to support the community.
She said: “It’s absolutely distressing. There aren’t words for it.”
Describing the area, she said: “It’s a very mixed and varied parish with all sorts of people living here, all sorts of people striving to make a good life and doing the best they can.
“The same as many communities, there’s people that do very well, there’s people that struggle, it’s a very mixed community.”
The arrested teenager was taken to Martlesham police station for questioning.
It is understood he had not been detained on suspicion of murder or manslaughter.
Police have appealed for anyone with information to come forward.