Kris Van Ooijen, 22, was apprehended thanks to “the very good cooperation” between police in the two countries, Aargau cantonal police said in a statement on Friday.
Switzerland has now put in a request to extradite him back to Aargau, with a court to decide in which secure institution he should be placed.
Van Ooijen escaped from the Königsfelden psychiatric hospital in Windisch in the early hours of last Saturday morning.
In 2013 he was convicted of murdering a 17-year-old girl when he too was only a teenager.
After connecting online, the killer and his victim met in person in August 2009 when Van Ooijen battered the girl to death with a piece of wood and hid her body in a forest in Sessa, in the canton of Ticino. It wasn't until June 2010 that the victim's body was found by a hiker.
Convicted by Aargau's youth court, Van Ooijen was judged to have a severe mental disorder.
He was sentenced to four years in prison – the maximum sentence for a minor – before being placed by the court in a secure psychiatric ward.