Massive manhunt for Oklahoma gunman who killed 3

ABC News' Olivia Katrandjian and Alyssa Newcomb report:

Local and federal investigators are searching for a lone white male in a pickup truck who went on a shooting spree in Tulsa, Okla., early Friday morning, killing three pedestrians.

Five black males were shot, three fatally, in four separate incidents during a span of less than two hours on the same side of town and not far from one another, police said.  Two males were critically wounded in the shooting spree. All of the victims were targeted while they were out walking.

The suspect is reported to be white, but the crimes have yet to been deemed racially motivated. The task force's job will be to determine whether federal hate crime laws were violated, Tulsa World reported.

The FBI and the U.S. Marshals are assisting in the investigation.

Police Chief Chuck Jordan said "logic would lead you to believe that" these are hate crimes, but the police haven't yet assessed all of the evidence to make that determination.

Sgt. Dave Walker of the Tulsa Police Department says the victims apparently did not know each other.

"We have not been able to find any commonality between the victims other than they were walking on the street," said Walker.

But Dr. Warren Blakney, who heads the local chapter of the NAACP, believes the shooter did group his prey together.

"We feel like he's targeting African Americans in this part of town.  And I think some parts of law enforcement feel the same way," said Blakney.

Jordan, who described the suspect as a "Lone Wolf," said police are actively pursuing tips in the case and asking residents to contact police if they've seen anything.

"This is one where we have to stand together with our community. We need their help, we want their help and we hope we will get some good calls to give us some leads," Jordan said.

"We are doing what we can do, someone needs to step up and somebody needs to come forward and say you know we know who did this," Walker told ABC affiliate KTUL.

Police are looking for a white male driving a white pick-up truck, the station reported.

"As long as that person is loose, then we're in danger, all of us are in danger, and I don't want any vigilante stuff to start happening. I don't want no race riot, I just want this person caught," said City Councilor Jack Henderson.

Tulsa Mayor Dewey Bartlett says the shootings are hard to stomach.

"It pains me to talk about such a violent event that we in this community have not seen certainly in modern history," said Bartlett.  "We as a community need to be very involved with helping the police bring this person to justice.  This is not a game."

Troy McMullen and ABC News Radio contributed to this report.