Anoka County authorities are searching for a man who is suspected of kidnapping a 5-year-old girl and killing a 21-month-old toddler.

Law enforcement is searching for Nelson Geovanny Soto-Lopez, 24, who was last seen walking away from a home in the 2000 block of Todd Drive in Arden Hills around 9:30 a.m. on Tuesday, according to the Anoka County Sheriff’s Office.

Soto-Lopez is suspected of kidnapping Cristal Mariel Olivia Aguilar, 5, who is not his child. Earlier Tuesday morning, officers responded to an incident around 7 a.m. at the Blaine Medical Center, where a 21-month-old boy was found dead.

“There is information to suggest he may be attempting to leave the Twin Cities metro area,” the Sheriff’s Office said in a statement.

Authorities said at an afternoon news conference that they have arrested the missing child’s mother, Heidi Jacqueline Agui­lar-Bastillo, on suspicion of aiding an offender and endangering a child. During the investigation, Aguilar-Bastillo’s accounts were “varied and inconsistent,” said Cmdr. Paul Sommer, a spokesman for the Sheriff’s Office.

Authorities suspect that Soto-Lopez is Aguilar-Bastillo’s boyfriend.

Acquaintances last saw Soto-Lopez on foot in Arden Hills, walking toward Hwy. 96, with the 5-year-old, said Sommer.

“We don’t know what his intentions are for the child, and we are gravely concerned for her,” the commander said.

The investigation is focusing on an apartment in the 1500 block of 87th Avenue NE. in Blaine.

Anoka County detective Jeffrey Olson could not say whether authorities had received calls for service to the Blaine residence where they’re now investigating, but Sommer said the office had no record of “ongoing” police contacts with the suspects.