Federal and state investigators in New Jersey are hoping renewed attention could help crack a 23-year-old cold case over a missing South Jersey boy.

Mark Himebaugh, 11, disappeared from Del Haven in Middle Township, NJ in November 1991 after he had apparently gone to check out fire department activity near his home. Some news accounts say he was last seen playing with an unidentified girl. Investigators found his left shoe on the beach about 75 yards from his home. 

Himebaugh was taking the antidepressant prozac at the time of his disappearance, and was known to have tantrums and outbursts, investigators said.

Roughly 30 investigators conducted a cold case review of the Himebaugh case in February. Law enforcement officials today are set to announce additional assistance from the National Center for Missing and Exploited Children Project Alert Program. 

About 170 retired law enforcement investigators contribute to Project Alert, which helps conduct case review, organizational analysis, consulting on investigative strategies and other technical assistance.

Investigators believe Himebaugh was abducted by a stranger.