"I picked it up, it was about 10 o'clock at night, the parking lot was absolutely empty," Monroe said.
Eyewitness News is not showing the entire watch on-camera, because only the rightful owner would be able to properly identify it. The watch sells for nearly $2,000.
"First thing I thought of was, 'Oh my gosh what if it was somebody's husband [who] had passed away,' or sentimental value," Monroe said.
Among other methods, Monroe has checked Craigslist to see if anyone reported it lost.
"I've sent e-mails to people, I've checked with the bank, I went to the business park," she said.
The airline baggage handler says some friends told her just to keep it because her family could use the extra money.
"They were like, 'Christmas money! Try to sell it!' But I was like no. I believe in trying to find the person because this is somebody else's, it's not mine," she said.
The Oklahoma native sees this as her chance to return an act of kindness she received last year when someone turned in her lost car keys.
"I was very thankful," Monroe said.
Monroe filled out a report and turned the watch over to Irvine police.
"We'll make every effort we can to reunite the property with the owner," said Irvine police Lt. Julia Engen.
Irvine police will hold on to the watch for 90 days. If the rightful owner has not come forward within that time, Monroe will get to keep it.
The rightful owner of the watch should call Irvine police at (949) 724-7199.