BERLIN (Reuters) - German police have arrested a 60-year-old landlord after discovering he used cameras and microphones to spy on his tenants for a decade while they bathed and slept.

The man had installed surveillance in the bedrooms, bathrooms and living areas of two flats 10 years ago in the southern city of Ingolstadt, Bavarian police said Tuesday.

He taped at least seven current and previous tenants -- and an unknown number of their guests.

He was arrested on charges of invasion of privacy after one of his tenants discovered the bugging last week while she was cleaning the flat.

The landlord admitted to police he had been watching and recording tenants and guests. Police suspect he had sexual motives.

“Why do you think someone would put a camera in the bathroom -- to see if it was being cleaned correctly?” asked Bavarian police spokesman Ulrich Poepsel.