LINDEN - Police arrested 20 people following drug raids in Union County over Easter weekend.

A house on Grier Avenue in Linden was among 10 locations raided. Investigators say it was a heroin mill.

The arrests included two alleged high-level Bloods gang members and several street dealers.

Authorities confiscated more than a $500,000 in heroin, cocaine and marijuana.

An estimated 25,000 prescription pills, the largest quantity ever seized in Union County, were also collected.

"This is one of the largest investigations we've seen in several years," says Acting Union County Prosecutor Grace Park. "The amount of seizures...It's the largest amount of prescription drugs that we've seized in the county."

A yearlong investigation led to the raids.