SAMUT PRAKAN: A woman jumped into a canal from a bridge on the Bangkok-Chon Buri motorway in Bang Bo district late on Monday night, leaving her a car on the bridge and her three-year-old daughter inside it.
She has not been seen since.
Pol Capt Jatuporn Boonprasong, a Bang Bo duty officer, said a highway patrol found a car with a child inside it parked on the bridge at kilometre marker 28 on the motorway about 1am on Tuesday.
It was on the bridge over Klong Phra Ong Chao Chaiyachit.
Police and rescuers sent to the scene said a three-year-old girl was sleeping in the front passenger seat. There was no driver.
A check found that the car belonged to Nicha Khemkornsukjit, 34, who lived in Bangkok's Suan Luang district. Ms Nicha's mobile phone was left in the car. Police used it to call her relatives to take care of the child.
Local resident Prairoj Sornkaew, 47, said he was fishing under the bridge shortly before midnight and heard someting heavy fall into the canal, causing a large splash.
Soon afterwards, a highway police car arrived, and he was asked about the car parked on the bridge.
Police believe the driver had jumped into the canal, leaving her daughter in the car.
Divers from the Ruam Katanyu Foundation started a search for the woman.
The missing driver's mother, Pranee Montree, arrived to take care of her granddaughter.
Mrs Pranee said her daughter had familiy problems. She married a Chinese man but they had separated and he returned to China, she said.
Ms Nicha had hurt her daughter twice out of stress, and she had taken the child into her care.
Early on Monday night, Ms Nicha called and said she would collect her daughter. She later took the girl away in her car despite her protests, Mrs Pranee said.
The search was continuing for Ms Nicha.
Rescue workers arrive at a bridge on the Bangkok-Chon Buri motorway in Samut Prakan's Bang Bo district. (Photo supplied: Sutthiwit Chayutworakan)