The paperwork shows Merritt Jr., the suspect in four of the cases, pawned a handgun for $75 to Glendale pawn shop Mo' Money Pawn.
The store offered to sell the gun back to Merritt later, as long as he included an interest payment of more than 200 percent interest.
Merritt pawned and bought back the gun several times from the store in the months before his arrest.
Those financial decisions, along with budgets and pay slips, paint the picture of a financially distressed family, which might have contributed to Merritt's arrest.
DPS found Merritt because they found the handgun they were looking for at Mo' Money; had Merritt not allegedly pawned the gun, detectives might not have made the arrest, or at least not as quickly.
Detectives also requested cell phone data from every cell phone that was used in the area of the first four shootings during the time frame of each respective shooting.
Investigators wanted to know if any individual cell phone was in the area of all four shootings. If so, detectives wanted that cell phone owner's name.
Merritt has maintained his innocence and is due back in court later this month.