CHICAGO (CBS) — A new team from the Cook County Sheriff’s Office has launched an effort to seize guns from thousands of people whose state gun permits have been revoked.

WBBM Newsradio’s Bernie Tafoya reports more than 3,000 people in Cook County have failed to surrender their revoked Firearm Owner’s Identification cards, but Sheriff Tom Dart said most people with revoked FOID cards don’t get rid of their guns.

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Illinois residents must have a valid FOID card to possess a gun. The state can take away a FOID card from anyone who has been convicted of a felony, declared mentally ill, or had a restraining order imposed against him or her.

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Dart has sent out a team of sheriff’s deputies to confiscate FOID cards and any illegal firearms from residents whose gun permits are no longer valid.

The sheriff has assigned a sergeant and four investigators to the gun team, and since February they have recovered about 160 revoked FOID cards and more than 160 guns. In one seizure, the officers took 35 guns, including four AR-15 assault rifles, from a suicidal man with a revoked FOID card.

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One investigator said what makes his job so rewarding is, when officers remove a gun from a person’s home, some family members who were scared of the gun owner thank police, because they didn’t want the weapons around.