(CBS) — A 23-year-old man has been missing from his Roseland home for a month now, and his family says they’ve been asking police to search a lagoon for his body.

“I believe my son was killed,” says Bonnette Jernigan, the mother of Iaron Brooks, who disappeared last month.

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“That’s where we are right now, 78th and Normal, because I got a strong tip that my son is in this lagoon, that his body is in this lagoon,” she says.

The family is upset that police haven’t searched the lagoon. Iaron Brooks’ uncle, Ricky Pittman, says authorities don’t hesitate to use their resources to rescue animals on the frozen lake.

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Chicago Police say they’ve been to the lagoon twice but it was frozen.

The family says they think it’s still possible to search there.

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Police say they have not received any intelligence that Brooks’ body is in the lagoon.