Alabama authorities say they believe a former high school coach and teacher has had inappropriate contact with multiple victims over the course of many years.

Authorities are reaching out to the public to help identify victims of former coach William “Billy” Gardner who was arrested Friday and charged with transmitting obscene material to a child and solicitation of a child by computer, which is a felony.

Citronelle Police Chief Tyler Norris said Friday’s arrest stemmed from a joint investigation by his department, the Washington County Sheriff’s Office and the US Department of Homeland Security.

Norris said investigators discovered text messages and other material on devices that confirmed that Gardner was having inappropriate contact with a 15-year-old female, a relationship that Norris said developed several years ago when the victim was in the sixth grade.

Norris said investigators believe that the 15-year-old female is not Gardner’s only victim.

“We believe there are multiple victims in this case,” Norris said. “We want to give the victims an opportunity to come forward.”

Norris said evidence that has been collected — including the seizure of multiple devices — suggests Gardner’s actions are not isolated.

“It has been going on for quite some time,” Norris said.

Norris said he suspects the number of victims are “quite a few.”

Norris said Gardner has been a coach and teacher in several schools since 1999.

The approximate dates of Gardner’s coaching career are:

• Fall 1999 through Fall 2002 — Citronelle High School
• Spring 2003  through Spring 2007 — Satsuma High School
• 2007-2008 school year — Baldwin County High School
• Fall 2008 through Spring 2010 — Jackson High School
• Fall 2010 through Spring 2011 — Milry High School
• Fall 2011 through 2012 — Citronelle High School
• Summer 2014 through Spring 2015 — Milry High School
• Fall 2015 through Spring 2017 — Chickasaw High School
• Spring 2017 through Spring 2018 — Leroy High Schoo