A 12-year-old Hong Kong boy who wrote a pubic letter thanking police for finding his lost young sister on a bus has now admitted he left his sibling on the vehicle.

The boy wrote the letter to the Hong Kong Police Force on April 20, saying he and his nine-year-old sister, along with their domestic worker, took a KMB route 1A bus heading to Kowloon’s Sau Mun Ping after school at about 4:40pm, Sing Pao Daily reported.

“I carelessly left my younger sister, who was sleeping, on the bus,” Chan wrote, adding he did not notice his sister was still on the bus when he got off with the domestic worker.

After discovering his sister was missing, he immediately informed his father before calling 999 for police assistance. The boy said three police officers who were patrolling on nearby Sau Ming Road helped him find his younger sister in 30 minutes. The girl was unhurt.

The boy said he appreciated the prompt action by police. Chan thanked the officers from the Ngau Tau Kok Police Station for their efficiency and hard work.

Media reports did not tell whether the domestic worker was blamed by her employer after the incident.