OKLAHOMA CITY - Heroin overdoses have claimed the lives of seven people in just seven days, according to the Oklahoma Bureau of Narcotics. Now the race is on to find out if they're connected and the source before someone else dies. 

OBN says five of the victims were in Oklahoma City, and in at least two of these cases, fentanyl may have been involved. OBN says it’s a good indication a potentially potent batch may have reached the Oklahoma metro.

“Fentanyl can be as strong as heroin or 10,000 times stronger than morphine depending on who is manufacturing it,” said OBN spokesman Mark Woodward.

It's a powerful drug that, Woodward says, is often used to cut or lace heroin.

“A lot of drug traffickers and organizations use it to backfill drugs especially heroin, because it can mimic the effects of heroin, but be cheaper and much more powerful,” said Woodward.

That power, its potent high, is something Woodward says users are always chasing.

“One of the characteristics of heroin use is seeking a stronger high as their tolerance grows, and of you can put a drug out on the street that will increase the demand for it,” said Woodward.

Due to the fact that the drug is sold illegally, and on the streets, Woodward says users never know exactly what they're getting.

“A lot of the times the dealer that you are buying from does not know what's in that batch, they got it from a guy, who got it from a guy, who had it smuggled in here from another state and another country,” said Woodward.

OBN reports since May 27, seven Oklahomans have died from heroin related overdoses, including five in Oklahoma City and two in Tulsa.

“Seven in seven days is very unusual, and we are looking into the possibility that it could be connected to a single batch or multiple batches that maybe come from the same source,” said Woodward.

By the time a user realizes they got more than they bargained for, Woodward says it's often too late.

“These heroin users don't know what they're buying until they end up in the hospital or dying from an overdose,” said Woodward.