Federal immigration authorities think all three of the Durham men jailed Wednesday in connection with a recent double murder and double attempted murder may be in this country illegally, a Wake County jail spokesman said.

Police say the shootings occurred Saturday afternoon at a Southeast Raleigh rental home that was being used as a brothel. Investigators say the men fled in a dark blue minivan that was thought to be a late 1990s model, possibly with lightly tinted windows.

Agents with U.S. Immigration and Customs Enforcement have requested that retainers be placed on Rony Alvararo Martinez, 23; Elvin Adrian Martinez, 21; and Mauricio Castillo, 19, the jail spokesman said late Wednesday afternoon. The three men lived at 2920 Chapel Hill Road, Durham, police reported.

That means the men would be picked up by immigration authorities to face a federal judge who may have them deported.

The three Durham men are charged with shooting four people -- two fatally -- at 316 Sunnybrook Road in Raleigh.

Raleigh police spokesman Jim Sughrue said the suspects were arrested in Durham overnight.

Each suspect is charged with two counts of murder and two counts of attempted murder.

Police on Tuesday identified the dead men as Marco Antonio Alvarez-Martinez, 19, and Gregorio Lopez-Estrada, 23. Those wounded were Aquillino Padilla-Meza, 26, and Angelica Avendano-Pereda, 20. They were both treated at WakeMed's Raleigh Campus for injuries that were not life-threatening, police reported.

Police have not discussed a motive for the shootings.

Police also reported an armed robbery at that address about an hour before the shootings, according to records posted by police at www.triangle.com. But investigators have not yet said whether the two incidents are related.

The immediate area where the shootings occurred has been busy with reports of criminal activity in recent months, police reported. An arson in the 500 block of Sunnybrook Road occurred in May, a kidnapping was reported in the 600 block in April, and an aggravated assault was reported to police on Jan. 1.

The investigation into the shootings is continuing, Sughrue said Wednesday. He did not release additional information about the house's possible use as a brothel.

The three suspects are being held at the Wake County jail without bail, court records show.