
Lt-Colonel Danchai Tool-ong, an inspector of Pak Klong San Police Station, was alerted to the incident at about 2.45am.
When he arrived at the scene with rescuers and scuba divers of the Ruamkatanyu Foundation, he found a motorcycle parked on the bridge on the Thonburi-bound side.
A bag was found on a sidewalk near a pair of high heel shoes and a garland.
Inside the bag were a wallet and women clothes.
Danchai said a first-year student ID card from a vocational school was also found.
A witness told Danchai that he saw the teenager jump off the bridge.
People fishing on the river bank threw her a lifebuoy but she refused to grab it and disappeared under the water.
Danchai said the scuba divers had to wait until morning before they could search for the body.