A store was put into lock down after an absent-minded man took a shopping trolley that was not his own, only later realising that it contained a baby.

Police said that staff at a Hannaford supermarket in Portland, Maine, issued an alert after a parent reported his child was missing on 20 October. The father said that while he was momentarily distracted, the shopping cart containing his two-month-old baby in a car seat had disappeared.

The alert meant the store was on lock down, preventing anyone from leaving. However all ended well when the child was found in the bread aisle just a few minutes later.

Portland Police said that store surveillance showed a "man in the produce section leave his original cart and accidentally take the cart containing the baby".

The man was then said to notice his mistake within a minute by which time he had already moved to another section of the store.

"The man told police he panicked when he realised what he had done and regrettably did not notify store employees," Portland authorities said in a press release.

After review from the district attorney's office, no criminal action was found. The baby reportedly stayed asleep in the car seat during the entire incident.

"The mistake of taking the wrong shopping cart is understandable but is magnified because a baby was inside," police said. "The man's poor judgement by not coming forward and reporting his mistake caused increased stress for the parents and a lengthy police investigation".

Police chief Michael Sauschuck said: "We are pleased that we have been able to determine exactly what happened in this instance. It is a very frightening event for all parents and raised safety concerns in our community.

"It is important for our citizens to know that as disturbing as this incident was, it was not an attempt to abduct a child."