HOUSTON -- A $20,000 reward was offered on Monday to find whoever killed a Halliburton employee who was working toward his masters degree at UH, KPRC Local 2 reported.

Marcus Washington, 35, was found shot to death in his northwest Harris County apartment on July 3.

Investigators have no witnesses, no murder weapon and no motive.

"At this point, we have no leads and no suspects," said Sgt. Ben Bell with the Harris County Sheriff's Department.

Since the investigation has hit a dead end, law enforcement officials and Washington's family asked for help.

"Crime Stoppers and private sources are offering a reward of up to $20,000," said Amy Smith, with Crime Stoppers.

Washington was last seen alive at 8:30 a.m. on July 3. His body was found by his roommate when he came home to the Carriage Place Apartments in the 500 block of Wells Fargo Drive around 7:30 p.m.

Washington left behind a large, loving family.

"We're just devastated as a family that something like this could happen to him. We're just asking for anyone that knows any info about this case and at this time to please call in to Crime Stoppers, and to give info so that our family can have closure," sister Tamara Washington said.

Washington worked for Halliburton as procurement specialist. He was off work the day he was killed and planning to join friends for a July Fourth motorcycle outing.

Anyone with information is asked to contact Crime Stoppers at 713-222-TIPS.