Three persons, including a woman and her son, were killed when the tourist bus they were travelling in went out of control, and fell into the nearby Peringathur river early on Tuesday.
The bus was on its way from Bengaluru to Thalassery when the mishap occurred about 15 km from here, police said.
While the bus driver escaped with injuries, the cleaner lost his life, they said.
Two passengers, Pramalatha and her son Prejith, natives of Chockli in Kannur district also died, they added.
The bus hit the railing of the bridge and fell into the river.