LUDINGTON, Mich -

Prosecutors are dropping one of two charges against a West Michigan father in the disappearance of his baby daughter.

The Ludington Daily News and The Muskegon Chronicle report prosecutors this week said they were dropping a parental kidnapping charge against 21-year-old Sean Phillips of Victory Township. His trial on an unlawful imprisonment charge is set for April 16 in Mason County Circuit Court in Ludington.

Prosecutors say the decision was a strategic move ahead of trial.

Katherine Phillips was 4 1/2 months old when she last was seen June 29, 2011, with Phillips. Katherine lived with her mother Ariel Courtland in Ludington, about 80 miles northwest of Grand Rapids. Extensive searches haven't found the girl.