Farmer Tony Martin has been told he will not face any charges over allegations that stolen number plates were found in his car.
The Tony Martin case caused a massive public outcry
Cambridgeshire Police confirmed on Wednesday that the Norfolk farmer had been released from police bail and that no charges would be brought.
The 59-year-old eccentric was jailed for shooting a burglar at his home five years ago.
No details of why the decision has been taken have been given.
Martin had been arrested earlier this month after an officer spotted the stolen licence plates in his car near Wisbech.
Brendan Fearon was seriously injured in the shooting
His friend and supporter Malcolm Starr said he had received a letter on Wednesday from the Cambridgeshire force saying police are cancelling Mr Martin's bail notice.
"He was expecting them to charge him. From his point of view he feels police went over the top when they first confronted him," he said.
"If they'd had a different attitude than the one that made him feel as if he had done something wrong he would have co-operated and this wouldn't have been blown out of all proportion.
"Mr Martin would never have stolen any licence plates or had stolen licence plates in his possession."
A spokesman for Cambridgeshire Police said: "The 59-year-old man from the Wisbech area who was arrested on 12 February under suspicion of theft from a motor vehicle has had his bail cancelled.
"He will no longer be reporting to Wisbech Police Station on 2 March."
Served three years
Martin was released from jail last summer after having served three years of a five-year term for shooting dead intruder Fred Barras, 16, at Bleak House, his remote farmhouse in Emneth Hungate, in 1999.
A second burglar Brendan Fearon, 33, from Newark, Nottinghamshire, was seriously injured in the incident.
There was a huge public outcry when Martin was found guilty of murder at Norfolk Crown Court and jailed for life for the killing.
The charge and sentence were later reduced on appeal to five years' imprisonment for manslaughter and he was freed six months ago.