JACKSONVILLE, Fla. -

Police in Jacksonville are trying to identify a man they said robbed four Mandarin pharmacies since May 12 and tried to hold up another.

The latest holdup was Wednesday night. Officers called to the Publix on San Jose Boulevard at Mandarin Road about 7:15 p.m. were told the robber went into the store, approached the pharmacy counter and demanded a prescription narcotic. Police said he threatened to pull out a gun if his demands were not met, but no weapon was seen.

The robber obtained the narcotic and fled the store in an unknown direction.

Police said the robbery is believed to be connected with three additional robberies of supermarket pharmacies in Mandarin. In each of the cases, the robber has the same physical description and threatens to display or use a gun, but none is shown.

IMAGES: 4 robberies in 5 weeks

On Monday, a man held up the pharmacy of the Winn-Dixie on San Jose at Loretto Road. In that case a witness told Channel 4 the robber apologized and said he needed the drugs for his wife who has cancer.

"He's using a sob story to say that his wife has a serious illness, working on the sympathy of the people but he's robbing. He's committing a crime while he's doing it," said Channel 4's crime analyst Ken Jefferson. "He, deep down, understands that he will eventually be caught."

The series of pharmacy robberies appeared to begin May 12, when a man attempted to hold up the Walgreens on San Jose Boulevard just north of Interstate 295 in the afternoon, then robbed the Publix on Old St. Augustine Road by I-295 just 16 minutes later.

The same man is suspected in a May 30 robbery at the Publix in the 10500 block of San Jose Boulevard.

Anyone with any information on the man's identity or whereabouts is asked to call the Jacksonville Sheriff's Office at 904-630-0500 or Crime Stoppers at 866-845-TIPS.