Investigators say Ray Rouse IV, 34, was headed the wrong way down Wade Avenue on March 17 around 1:15 p.m. when his car slammed head on into another car.
The occupants of the second car - 83-year-old Ormond Bailey and 79-year-old Gaynell Bailey - were both killed.
The search warrant filed with a judge by Raleigh police seeks permission to examine Rouse's cell phone which was found at the crash scene.
It says a witness reported Rouse was coming from a brunch where he had been consuming alcohol. The warrant also says emergency personnel noticed a strong odor of alcohol on his person and clothing at the crash scene.
Other warrants also seek to examine data recorders from the vehicles for information about speed and braking, etc.
According to court records, Rouse was convicted of DWI in September 2001 and sentenced to probation. He was again charged with DWI in 2006, but the case was dismissed.
In an ironic twist, Rouse chanced to have been interviewed by ABC11 at the 2012 St. Patrick's Day parade.
He and a friend were giving out beads and the friend said they hoped people wouldn't drink and drive.
"Especially on St. Patrick's Day, which is a beer drinking time," Rouse offered.
Rouse was listed in critical condition Friday at WakeMed.