Police in Manchester, New Hampshire said they have narrowed down the timeline for when the body of a newborn girl may have been placed in the water at a park last week.

The newborn baby girl was found floating in the water off of Brown Avenue at Pine Island Park on Thursday at around 4 p.m. Police were called to the scene after getting a 911 call about an object floating in the water.

Trying to track down baby's mother

Investigators now believe the baby was placed in the water sometime between Tuesday, March 25 and Thursday, March 27, when she was found. They said this is important in helping them track down the baby's mother.

The baby's death is unknown at this point but police are calling her death suspicious. Her identity has not been released.

Police have also announced a $2,500 cash reward for any information that helps them solve this case. They said they've received more than 50 tips already and they're hoping for more.

Police asking for tips

"We're looking for information from anybody who may have seen somebody discarding an object into the water between March 25 and March 27," said Manchester Police Chief Peter Marr. "If anyone has photographs or videos taken at Pine Island Park and Pine Island Pond during that time, we ask that you send those to us. We're also still requesting information about anyone who was pregnant during that timeframe who is no longer pregnant and does not have a newborn baby with them."

Police are asking for anyone with any information to call them at 603-716-7236 or anonymously via the Manchester CrimeLine at 603-624-4040. Tips and photos can also be submitted anonymously to the Crimeline website.