The injured baby whale that was lost in London's Thames river was euthanized after being stranded for the second time.

• A young minke whale was rescued from a shallow area of London's River Thames on Sunday.
• But when it was transported to another part of the river it got loose and became lost again.
• The whale was found again on Monday and was euthanized because it was in poor condition.

The injured whale calf that went missing for the second time after rescuers freed it from being trapped in the London's Thames River on Sunday has been euthanized.

The British Divers Marine Life Rescue said in a statement that the young 13-foot-long minke whale was "humanely put to sleep" after its condition deteriorated throughout the day.

"Medics used inflatable pontoons to prevent the animal from slipping back into the river, which allowed the veterinary team from the Zoological Society of London to further assess the animal and end its suffering," the statement read.

The whale was rescued on Sunday and brought to another location but officials said they lost sight of it overnight.

At the time, a spokesperson for the Royal National Lifeboat Institution told The Guardian that the whale was "displaying concerning behaviors," and there was worry it could be "unwell."

Officials found the whale again on Monday against the river wall and were concerned that it could become beached again, CNN reported.

BDMLR said the Cetacean Strandings Investigation Programme would conduct a post-mortem exam to get a better understanding of why the young whale fell into poor condition and became lost in the river.