TWO RIVERS, Wis. (AP) — Wisconsin police searching for a 3-year-old boy who vanished last month said they have confirmed that a blanket found during their ongoing search belongs to the missing youngster.

The red and white plaid blanket belonging to Elijah Vue was found “earlier in this investigation” about 3.7 miles from where the boy was reported missing on Feb. 20, Two Rivers police said Monday in a Facebook post.

The youngster was last seen at a residence in Two Rivers, located about 30 miles (48 kilometers) southeast of Green Bay, where prosecutors said his mother had sent him to stay with her boyfriend. Searches by police and residents have so far not located Elijah, and police said the reward for information in the case has grown to $40,000.

Elijah’s mother, Katrina Baur of Wisconsin Dells, was charged last month with one felony count of party-to-a-crime child neglect and two misdemeanor counts of resisting or obstructing an officer. Prosecutors later amended the felony count to a charge of party-to-a-crime chronic child neglect and also filed a misdemeanor charge of neglecting a child against Baur, who is being held on a $15,000 cash bond.

According to a criminal complaint, Baur, 31, had left her son with her boyfriend, Jesse Vang, 39, on Feb. 12 because she wanted him to teach him “to be a man.”

Vang called police Feb. 20 and reported the boy missing, telling police he had taken a nap and brought the 3-year-old in the bedroom with him, but when he awoke three hours later he was gone.

Vang was formally charged in February with one felony count of party-to-a-crime child neglect in Elijah’s disappearance. He is being held on a $20,000 cash bond.