Two D.C. legal professionals planned to use Twitter to find the owner of a lost camera that one of them picked up on the Metro on Tuesday. They turned it on, found a family picture presumably showing the camera’s owners and tweeted the image. They successfully campaigned to get it retweeted and promoted by outlets ranging from local television in Florida to @SCOTUSblog, which normally serves as a Supreme Court blog rather than a lost-and-found.

But after all that, some old-fashioned detective work rather than social media led them to the happy conclusion of their quest.

Brian Pandya, who found the camera on the Orange Line, brought it into his law firm. There, two employees looking through the pictures found images of a child’s birthday party at a particular gymnastics studio in south Florida on Dec. 2, 2012.

They called the gymnastics studio and asked if it would look in its books to see who hosted a party that day. And that led right to Sunny and Robert Riling.

“I cannot believe that someone found it. I am so thrilled,” Sunny Riling said Thursday afternoon, after she learned that the camera was about to be mailed back to her family in Cooper City, Fla. She said that her husband had left it behind on the Metro on the last night of their 10-day vacation to Philadelphia and Washington.

“My husband was devastated,” she said. They tried calling Metro’s lost and found, but it was closed. “I said, ‘No one’s going to find it. Forget it. It’s gone.’ ”

“He said, ‘I don’t even care about the camera.’ I said, ‘I know. It’s the pictures.’ ” The camera held two years of special snapshots of the Rilings’ children, ages 8 and 10.

She said that she has never used Twitter or Facebook, in part because she does not want her children’s photos on the Internet, but in this case, she is happy to make an exception. “I might even have to look into social media,” she said. “Now I’m seeing how it can be useful.”