The winner of a $26m (£18.5m) lottery prize may have left the ticket in a trouser pocket – and destroyed it in the wash.

Thursday marked the last day to redeem the winning ticket, which was sold at a convenience store in a suburb of Los Angeles, and no one came forward.

But Esperanza Hernandez, an employee at the shop, told the local Whittier Daily News a woman had come in the day before and said she had put the ticket in her trousers and it was ruined in the laundry.

Her claim is being investigated by California Lottery officials, with the store’s manager telling KTLA-TV that CCTV video showed the women who purchased the ticket. She is also someone known to staff at the store.

The rules say someone who believes he or she is a winner, must complete a claim form.

But Lottery spokeswoman Cathy Johnston said if someone has lost a ticket, they must also provide evidence they owned it, such as a photograph of the front and back of it.

The $26m prize can be taken in annual instalments or as a $19.7m (£14m) cash option.

If the prize is not claimed, the $19.7m will go to California public schools.

The store that sold the ticket will receive a $130,000 (£92,000) bonus.

It is uncommon for large jackpots to go unclaimed, officials said.

Four prizes of $20m (£14.2m) or more have gone unclaimed since 1997, including a $63m (£45m) jackpot from 2015, lottery spokesman Jorge De La Cruz told the Los Angeles Times.