EAST CLEVELAND -- East Cleveland Police say they are building a strong case against accused serial killer Michael Madison. Madison is charged in the deaths of Angela Deskins, Shirellda Terry, and Shetisha Sheeley.

Following a tip that Madison may have been involved in human trafficking in Mansfield, police and the FBI tell us they checked it out but could not find any credible evidence.

However, East Cleveland Police Sergeant Scott Gardner says theyfound more evidence in Madison's apartment.

Hesaid investigators found women's clothing in Madison's apartment, including some belonging to the victims.

They also found decomposition fluids in several rooms, including the kitchen.That leads them to believe that at least one of the victims was killed inside the apartment.

And police say they found a key on a lanyard that led them to the apartment of Shirellda Terry. Gardner said that piece of evidence helped them identifyTerry as one of the victims.

East Cleveland Mayor Gary Nortonsaid they continue to follow leads to see if anyone else was involved but, so far, they believe Madison acted alone.