A 60-year-old gem thief was jailed for switching out seven gems for pebbles in a $5.8 million diamond heist

• Lulu Lakatos, 60, posed as a gemologist visiting the Boodles jewelry store in Mayfair, London.
• She swiped seven diamonds in a clever sleight-of-hand heist, and replaced them with pebbles.
• Lakatos was found guilty on Wednesday and sentenced to five years and six months' jail.

A 60-year-old gem thief was jailed for swiping seven diamonds from a London jewelry store in a $5.8 million heist.

Lulu Lakatos, 60, swapped the gems for pebbles using sleight-of-hand, per a news release from the London Metropolitan Police.

Lakatos was part of an international gang that set their sights on the Boodles store along New Bond Street, in central London's Mayfair district. According to the police, during this March 2016 heist, Lakatos pretended to be a gemologist named "Anna," who was visiting London on behalf of a wealthy Russian investor.

Inside the Boodles store, Lakatos viewed the seven gems on behalf of the "buyer." The gems were then placed in a locked purse, to be transferred to the Boodles vault until the store received payment for the goods, per the Guardian.

But using sleight-of-hand, Lakatos quickly switched the bag containing the diamonds to one that contained pebbles, moving the loot into her handbag.

According to the BBC, the gems stolen were worth $5.85 million. They included a 20-carat heart-shaped diamond worth more than $3.06 million and a three-carat pear-shaped fancy pink diamond worth $1.53 million.

Lakatos managed to pull off the heist despite Boodles staff being suspicious of her. She left the store quickly, then passed the padlocked purse to an unknown woman. The gang then left the UK within three hours, per the Metropolitan Police.

Boodles staff x-rayed the locked bag the next day and found that while the items inside the padlocked purse were around the same size as the diamonds, there was something amiss. The store then opened the bag and found the pebbles.

Lakatos was arrested in France, and extradited to the UK on December 3 last year, said the police. The diamonds have not been recovered, per the Guardian.

"This was an audacious theft, carried out in plain view of experienced and professional staff at a renowned jeweler. The meticulous planning and execution of this theft reveal to me that those involved were highly skilled criminals," said Acting Detective Sergeant William Man, a member of the Metropolitan Police's Flying Squad, the team that hunted Lakatos down.

Lakatos was found guilty on July 28 and sentenced to five years and six months in jail.