Gunmen wearing Iraqi special forces uniforms have kidnapped a wealthy banker and his son after killing five of their bodyguards, police said Friday. Police found the bodies of three men who had been shot execution-style in northern Baghdad.

Sunni Arabs have been complaining for months that kidnappings and murder by Shiite-led commandos operated by the Interior Ministry are driving many Sunnis into the ranks of the insurgents.

On Thursday, the ministry announced an investigation into claims of death squads in its ranks after U.S. military officials indicated there was evidence to support the allegation.

Ghalib Abdul Hussein Kubba, director-general of the Basra International Bank, was abducted from his home in Baghdad's western Yarmouk suburb at about 9:30 p.m. Thursday, said Maj. Felah al-Mohammedawi.

The kidnappers arrived in a minibus and killed five guards at the house before seizing Kubba and his son, Hassan, who is a senior employee at the same bank, al-Mohammedawi cited relatives of the bank chief as saying.

"We think it is a criminal case because the bank director was not killed," al-Mohammedawi said. "We think the kidnappers will blackmail the family and they are after money. We have many similar cases of businessmen being abducted for money."

Police said no demands have been made to date.

Bank employee Kadhim al-Nuaimi said Kubba had headed the chamber of commerce in Basra, Iraq's second-largest city, 340 miles southeast of Baghdad, for about nine years during Saddam Hussein's regime.

After the U.S.-led invasion, Kubba moved to Baghdad to run Basra bank's branch in the capital, al-Nuaimi said. The bank was established in 1996 and also has branches in the southern Iraqi city of Najaf and Dubai in the Unite Arab Emirates.

Drive-by gunmen killed a cigarette salesman in Husseiniyah, a town about 20 miles northeast of Baghdad, early Friday, police said.

The bodies of three unidentified man who had been bound and shot in the head were found in two locations in northern Baghdad on Friday, police said. It was unclear who killed the men, but they were discovered in an area where multiple bodies have turned up after being killed in similar fashion.

In the death squad case, Iraqi security officials said the Interior Ministry probe would focus on a single incident involving 22 Iraqi policemen who U.S. authorities said were detained last month before they were able to kill a Sunni Arab man north of Baghdad.

The U.S. military has been fighting a tough battle to rebuild a legitimate Iraqi security force that it hopes will eventually replace American-led coalition forces and maintain order throughout the country.