(CBS) — A two-year employee of the Cook County Sheriff’s Office and two others have been charged in a contraband smuggling operation at County Jail.

37-year-old corrections officer Jermaine Hoskins is charged with official misconduct for allegedly trying to smuggle an ounce of marijuana into the jail to a detainee who was allegedly planning to sell it to other prisoners.

Cook County Sheriff Tom Dart says also arrested were 41-year-old Taveda Driver, who allegedly supplied Hoskins with the pot and 33-year old detainee Lawrence Pope, who is in the jail awaiting trial on aggravated domestic battery allegations.

Dart says Hoskins has admitted smuggling illegal items such as drugs, tobacco and cellphones at other times into the jail, as well.

Hoskins was arrested Friday when he arrived at the jail.

Sheriff Dart says the charges are the result of a two-month investigation involving the FBI.

The sheriff says 1-oz. of marijuana may not seem like a lot, but that inside the jail walls, it can be worth “thousands of dollars”.

Also confiscated from the corrections officer, Dart says, was a toothpaste tube cap which is usually used to measure marijuana being sold among detainees.

Dart says the arrest is “quite upsetting” to him because of how much money and effort is spent on screening potential candidates to be corrections officers.

He says he’s had staffers review the screening for Hoskins but that, “nothing has jumped out at us so far.”