MEDFORD - Police have stepped up their search for the man who they say shot and killed four people at a Medford pharmacy Sunday.

A surveillance video shows the shooter walking into Haven Drug Store and gunning down two employees and two customers. Police say the man filled a backpack with prescription drugs and then calmly walked out.

Police are continuing to scour Long Island for the killer and say they have received more than 250 tips from people saying they know the suspect's identity or whereabouts.

The community continues to gather at the scene, bringing flowers and cards in honor of the four victims.

The victims include a 17-year-old high school senior, a 45-year-old pharmacist from Centereach, a 71-year-old Medford man, and Jamie Taccetta, 33, who was set to be married in October. Taccetta's two daughters, ages 16 and 5, laid flowers today at the site of their mother's killing.

"My grandkids, they're going to miss their mother [terribly]," says Taccetta's mother, Pat, who visited the crime scene today for the first time.

Taccetta's father, Ralph, had a message for the suspect. "To kill four people, you're a punk," he said. "We're going to get you."

Suffolk police are offering a $5,000 reward for information leading to the suspect's arrest, and members of the Medford Chamber of Commerce voted this afternoon to add $500 to the reward money.

Anyone with information is asked to call Crime Stoppers at 1-800-220-TIPS. Police search for killer in Medford drug store massacreVigil held for teen victim of Medford pharmacy shootingPolice: 4 killed in apparent robbery at Medford pharmacy