“Three were arrested in Tallinn, Estonia and one in Stockholm. They are being held and we plan to submit a remand order tomorrow (Wednesday) to the Västmanland District Court,” Västmanland police spokesperson Börje Strömberg told the TT news agency on Tuesday night.

Among those arrested was the 32-year-old wife of the victim. She is being held on suspicion of instigating murder, the Aftonbladet newspaper reports.

A 21-year-old woman is also suspected of instigating murder.

Two more people, ages 46 and 31, are being held on probable cause of committing murder – the strongest level of suspicion – as well as for being accomplices to a murder.

The 45-year-old victim, dubbed an “oil millionaire” in the Swedish press, was shot dead outside his home in Fagersta the night of April 27th.

The man worked late in the evening before meeting his mother at 9pm for dinner at her house, which is located about 100 metres from his home, reports Aftonbladet.

About 30 minutes later the 45-year-old went to his house, only to come running out about 15 minutes later wearing only his underwear and a t-shirt, according to eye-witness accounts.

He had scratches on his face and had been shot in the neck.

He was headed back toward his mother’s house when another shot was fired, sending him to the ground.

Witnesses then saw a car quickly leaving the scene.

The car, which belonged to the victim’s company, was later found abandoned near a rest stop on highway 66 near the approach to Fagersta.

Local police in Västmanland had recently begun cooperating with the Swedish National Investigation Department (Rikskriminalpolisen) as well as the Estonian Central Criminal Police, according to Strömberg.

Police raids were carried out at various locations in Tallinn and Stockholm in connection with Tuesday’s arrests. However Strömberg refused to elaborate on what may have been confiscated or on whether or not the evidence strengthened suspicions against the four being held.

The murder victim was a successful businessman within the oil industry. But Strömberg emphasized there is nothing to indicate that the motive is connected to the man’s business activities.

“This has nothing to do with organized criminal activity or his business operations,” he said.

Strömberg refused to go into more detail about the possible motive.

He said that there is currently nothing to indicate that additional arrests will be carried out, but added that more people will likely be interviewed about the case.

The investigation is being led by the international prosecution office in Stockholm in cooperation with prosecutors in Tallinn.

Police expect the four suspects to be remanded in custody by the district court and that the three currently being held in Tallinn will eventually be brought to Sweden.

“After they are remanded in custody we’re going to request they be extradited,” said Strömberg.