Police had been called to Mr Martin's isolated farmhouse, Bleak House, in Emneth, Norfolk, late on Friday. He was arrested at a hotel in Wisbech, Cambridgeshire, on Saturday.
Officers have questioned the injured man, 29-year-old Brendan Fearon, about suspected burglary. Another man arrested in Emneth early on Saturday was also questioned in connection with a burglary.
Both have been released on bail until next month pending further investigation, but the injured man, who received gunshot wounds to the leg, is still being treated in hospital at King's Lynn.
Earlier yesterday the mother of the dead teenager, who lived in Newark, Nottinghamshire, spoke of her anguish at losing her only son.
Ellen Barras, 46, said: "I cannot believe what has happened. Everyone loved him very much. It was awful when the police came on Saturday evening. They took us down to Norfolk and we had to identify my boy's body." She admitted her son had been in trouble with the police but said it was not anything serious.
"He used to take the odd bit of scrap metal and garden tools," she said.
Mrs Barras, who was treated by a doctor for shock yesterday, was being comforted by her five daughters and other family members.
The teenager's aunt, Ann Ball, said: "We are all very shocked ... you do not think something as dreadful as this is going to happen."
Relatives and neighbours of Mr Martin said he had been the victim of a several break-ins recently at his dilapidated farmhouse. After the most recent burglary Mr Martin had moved many of his possessions upstairs in the hope of improving the safety of his property.
Forensic scientists were still carrying out a detailed search of the rambling Victorian farmhouse and surrounding gardens yesterday.
Bleak House stands about half a mile from the main road surrounded on all sides by trees and dense undergrowth. Stewart Mayfield, 48, a farmer who lives half a mile away, said: "Last time they took an antique chest and some of his personal family papers and photographs. Some of those papers turned up in a ditch. The police got no one for it."
Mr Mayfield said he had also been burgled three times in recent years and many villagers had similar problems.
Mr Martin's cousin, Ted Martin, said: "Not only has he been burgled twice recently but he has also had tools and things stolen."
His aunt, Joan Whitton, added: "We hope he will get all the support he needs from people who sympathise with what he's been through."
Mr Martin, a bachelor, is to appear before magistrates at King's Lynn today.Reuse content