NEW DELHI, May 21 (UPI) -- New Delhi police said thieves are pouring sleep-inducing gas into air conditioning units to knock out homeowners during burglaries.

Investigators said the thieves pour the gas into the window-mounted units, which fan air through wet grass, and wait for homeowners to fall asleep before relieving them of their valuables, Sky News reported Friday.


The gang took about $11,500 worth of cash and jewelry from a home this week and made off with $20,000 in of cash and goods earlier in the month.

Police said one of the victims reported a "revolting odor" coming from the air conditioning unit.

"The investigations are on and we have sent the water sample for testing and efforts are on to nab the people behind the crime," a police spokesman said.