Updated 01/04/12 – 6:34 p.m.

CHICAGO (CBS) — Chicago police officers went door-to-door in the Austin neighborhood on Wednesday, urging local residents to speak out about what they might know about the murder of an off-duty police officer last week.

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As CBS 2’s Derrick Blakley reports, police also stopped drivers to hand out flyers, hoping to learn new clues into the shooting death of Officer Clifton Lewis.

Lewis, 41, was shot and killed last Thursday night, during a robbery of the West Side convenience store where he worked as a guard. Police said they believe someone in the community has vital information they could use, although they didn’t directly accuse Austin residents of enforcing a code of silence or not cooperating in the investigation.

Police Supt. Garry McCarthy said police are doing everything they can to solve the murder, which is why they made the up close and personal appeal to Austin residents on Wednesday.

“We have a number of significant leads, we’re making a lot of progress in the case, but we have no arrests at this point,” McCarthy said as teams of Chicago police officers and cadets went around the West Side, knocking on doors, passing out flyers and alerting residents to a reward for information leading to an arrest and conviction.

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Fraternal Order of Police President Michael Shields said the union is boosting the reward fund.

“We have upped the reward money an additional $11,000 for any information leading to the arrest and conviction of the murderer of Officer Lewis,” Shields said.

The total reward is now up to $34,000. It includes $21,000 from the Police Memorial Foundation, $11,000 from the FOP, and $2,000 from several West Side churches, led by Rev. Ira Acree.

Austin resident James Ruffin said, “my message to my neighbors, if you know anything, say something. If you see something, say something; because we have to put a stop to this.”

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At the Austin District police station where Lewis worked, the entryway has been decorated in black and purple bunting of mourning. Police, ministers and local politicians gathered at the district on Wednesday to send a message to local residents.
“We’re going to pray; but not only pray, we’re going to do something. It’s time for us to say something. Somebody knows something,” Ald. Emma Mitts (37th) said. “You mean we can’t have a right to walk or work, go into a store? That’s wrong. Somebody better say something. How can you harbor such criminal activities in your homes?”

Police said they’ve actually had a flood of community tips.

“The point is, we haven’t caught the right bit of information,” McCarthy said. “People are telling us things, we chase them down and we find out that there’s not a lot to them.”

The question now is will cold cash move cold hearts?

Austin resident Jeddor Judda said, “If you know something, you know, you should come forward. The money shouldn’t make any difference.

Officer Lewis was killed on Thursday of last week, during a robbery at the M & M Quick Foods convenience store, 1201 N. Austin Blvd., where he worked as a security guard while off-duty.

Two masked armed men entered the store, and one of them immediately began firing, McCarthy said last week. He said Lewis, who was behind counter, was hit. One of the offenders was believed to be carrying a “Tec-9” semiautomatic, McCarthy said.

Lewis died from multiple gunshot wounds, according to the Cook County Medical Examiner’s office. He was an eight-year Chicago police veteran, assigned to the Austin District Tactical Unit.

He had just started working as part-time security guard for M & M Quick Foods after the store had been robbed a few months earlier.

Even though Lewis was off-duty as a police officer when he was gunned down, the Police Department says his death will still be considered in the line of duty since he was working security at the time.

A public wake for Officer Lewis is planned for Thursday. It will begin at 10 a.m., followed by an 11 a.m. funeral at United Baptist Church, 4242 W. Roosevelt Rd.

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Meanwhile, a reward of more than $10,000 for information leading to arrests and convictions in Lewis’s murder is being offered by the Chicago Police Memorial Foundation. A tip line has been set up to field calls at (888) 976-7468.