A note left after a break-in at the home of Liberal Party Leader Justin Trudeau cautions that another such incident could happen if his family doesn’t lock its doors, according to a police source.

Ottawa police and the RCMP are investigating a break-in at Trudeau’s home in Ottawa’s Rockcliffe Park neighbourhood between Friday night and Saturday morning.

Police were called to the home at about 9 a.m. ET after vandals broke in.

Trudeau’s wife, Sophie Grégoire-Trudeau, a house guest and Trudeau’s three young children — Xavier James, Ella-Grace and Hadrien — were asleep inside when the incident happened.

A police source said when officers went to the back door of the home, they found a letter purportedly left by the vandals. It was set on a pile of items including kitchen knives, the source said.

Letter urges family to lock doors

The letter stated items could have been stolen but weren’t, so the family should lock its doors in the future.

Trudeau was in Winnipeg before travelling to Montreal on Saturday for the city’s gay pride festivities.

He told media on Saturday his family was rattled by the break-in and left Ottawa to join him in Montreal.

Liberal Leader Justin Trudeau confirmed his Ottawa home was broken into Friday night while he was in Winnipeg, but his family was home at the time. (CBC) "While my family was sleeping somebody broke into our house while I was away in Winnipeg. Obviously we're extremely troubled by this," he said on Saturday.​

"Everybody's safe, but the idea of someone getting into the house while my family was sleeping [and] while I'm away working is very distressing, to say the least."

Nobody was hurt in the incident.

On Saturday, RCMP and a locksmith were also seen parked at Trudeau's home.