Jimmy really misses the tracker; actually, the FBI's tech department can provide GPS tracking devices. He should have applied for one in advance as a backup, which would have come in handy inside the other party's car.
Soon, several disguised police cars drove over. Woodlawn Cemetery has several entrances and you can actually drive inside. The routes inside are also complicated. Watching the disguised police cars circle around nearby before they entered the cemetery area one by one, leaving only one car parked not far from Jimmy.
Jimmy realized they were disguised police cars because he could see the people inside: two people per car, wearing bullet-proof vests. It's not easy to notice from the outside, but to Jimmy, their attire was too obvious.