A fourth person is being questioned in connection with the death of a businessman who was fatally shot during a botched burglary.
The man, 40 and from the Blandford area of Dorset, is being held on suspicion of murder and aggravated burglary after handing himself in to Dorset Police.
Two men and a woman remain in custody after Gary Hedger, 61, was killed in the early hours of April 30 after at least two intruders entered his £1 million home in Castlewood, Dorset.
A 41-year-old Bournemouth man has been arrested on suspicion of murder and aggravated burglary, while a 44-year-old Bournemouth man and a 40-year-old Bournemouth woman have been arrested on suspicion of conspiracy to commit murder and conspiracy to commit aggravated burglary.
Superintendent Kevin Connolly said: "In total four arrests have now been made.
"However, our enquiries still continue and our appeal still stands for anyone with information that could aid us to come forward.
"This is the case for anything relating to suspicious activity after 3am on Sunday 30 April 2017 in the Verney Close area of West Howe and in Winterborne Stickland as well as information about anyone acting unusually in Castlewood in the days or hours leading up to Guy Hedger being killed.
"We would like to thank everyone who has contacted us already. The support we have received from the public has been encouraging."
A post-mortem examination found Mr Hedger died as a consequence of gunshot wounds, the force said.
The alarm was raised at 3.03am on April 30 when police received a call reporting Mr Hedger had been shot with a shotgun.
The insurance executive was pronounced dead shortly after arriving at hospital.
It is believed jewellery, including designer watches, was stolen from the address.
Mr Hedger's partner, Simon-Pierre Hedger-Cooper, 48, a voluntary sector worker, was also in the house at the time.
On Tuesday, Mr Hedger's family paid tribute to him.
In a statement, they said: "Guy was a caring and compassionate partner, son, brother and uncle who lived life to its full and enriched the lives of all those who knew him.
"We are devastated that Guy's life has been cut short in this way.
"Guy will be sorely missed by family, friends and colleagues, but he will live in our hearts forever."
Mr Hedger was a director of the Avonbourne International Business and Enterprise Trust, which runs colleges and a primary school in the Bournemouth area.