Lulu the bomb-sniffing Labrador has been dropped from the CIA's explosives detection programme because she was "no longer interested in searching for explosives."

The 18-month-old dog "was clearly not enjoying herself any longer," the agency said, adding it was "sad to announce" she had been dropped from training for the Fairfax County Police Department in Virginia.

"Sometimes, even when a pup tests well and they successfully learn how to detect explosive odours, they make it clear that being an explosive detection K9 is not the life for them," the CIA said in a post on its website.

Following a 10-week training programme, the dogs are expected to be able to sniff out 19,000 explosive scents.

But the CIA said Lulu had begun to "show signs she wasn't interested in detecting explosive odours" a few weeks into her training.

"All dogs, just like most human students, have good days and bad days when learning something new. The same is true during our puppy classes.

"A pup might begin acting lazy, guessing where the odours are, or just showing a general disregard for whatever is being taught at the moment. Usually it lasts for a day, maybe two."

The agency said "there can be a million reasons why a particular dog has a bad day," with its trainers becoming "doggy psychologists" to figure out what will help them.

Sometimes they are bored and need extra playtime or challenges, the CIA explained, sometimes they need a break or have a food allergy requiring a change in food.

"But for some dogs, like Lulu, it becomes clear that the issue isn’t temporary. Instead, this just isn’t the job they are meant for.

"Lulu was no longer interested in searching for explosives. Even when they could motivate her with food and play to search, she was clearly not enjoying herself any longer."

The CIA then made the "extremely difficult decision to do what's best for Lulu and drop her from the programme."

"We’ll miss Lulu, but this was the right decision for her. We wish her all the best in her new life."

But the story has a happy ending.

Lulu was adopted by her handler, and now spends her says "playing with kids, sniffing out rabbits and squirrels in the backyard, and eating meals and snacks out of a dog dish."