Suspicion follows Mac
Scratches and secretive behavior convince Frank that Mac is the serial killer. Mac is actually concealing his renewed relationship with Carmen.
Supporting source ↗CASE FILE · S03 E10
Mac is a Serial Killer
S03 E10Photograph not available
Mac has been acting strangely, leading Frank, Dennis and Dee to believe that he's the serial killer who has been terrorizing Philadelphia. So they set out to catch him, but for Dennis and Dee, that means they must first learn to think like serial killers themselves. Frank, meanwhile, is content to let a chainsaw do his thinking for him.
THE SHORT VERSION · SPOILERS AHEAD
INSIDE THE CASE.
Charlie’s legal practice
Charlie appoints himself Mac’s defender, borrows his cologne and obstructs Frank’s questioning of Mrs. Mac.
Supporting source ↗Investigators become stalkers
Dennis and Dee dress as a painter and a clown to follow the Waitress. Their attempt leaves them washing their eyes at the bar.
Supporting source ↗The wrong suspect, the right apartment
The gang lures Mac to Gary’s apartment. Mac explains his behavior; the refrigerator then reveals evidence against their absent host.
Supporting source ↗THE EVIDENCE
THINGS IN THIS EPISODE.
Characters
Charlie Kelly180 other recorded episodes
Charlie puts his feet on the desk while playing lawyer.Source ↗
Dee Reynolds179 other recorded episodes
Dee wears a clown costume while washing her irritated eyes.Source ↗
Dennis Reynolds176 other recorded episodes
Dennis crouches in white work clothes beside Dee.Source ↗
Frank Reynolds171 other recorded episodes
Frank holds the chainsaw beside Charlie.Source ↗
Pepper Jack1 other recorded episode
Pepper Jack confronts Dee outside at night.Source ↗
The Waitress38 other recorded episodes
The Waitress cleans a table inside the coffee shop.Source ↗
Locations
Hardware stores2 other recorded episodes
Dee and Dennis browse a crowded tool aisle.Source ↗
Paddy’s Pub147 other recorded episodes
The gang discusses the investigation around the bar.Source ↗
Objects
Camcorders17 other recorded episodes
Dee points a camcorder at Mac during the staged interview.Source ↗
Drakkar NoirOnly recorded here so far
Charlie borrows Mac’s Drakkar Noir while searching his room.Source ↗
Fraggle Rock thermos1 other recorded episode
Dennis offers his Fraggle Rock thermos during the confrontation.Source ↗
Garden shears1 other recorded episode
Dennis holds open a pair of large shears.Source ↗
Refrigerators1 other recorded episode
The group discovers Gary’s refrigerator contains severed heads.Source ↗
Food & drinks
Schemes
Costumes
Clown costumesOnly recorded here so far
Dee wears a bright patchwork clown suit and face paint.Source ↗
Painter’s overallsOnly recorded here so far
Dennis wears pale work clothes and a painter’s cap.Source ↗
Rubber gloves8 other recorded episodes
Frank wears blue gloves while searching the bedroom.Source ↗
FOLLOW THE THREAD
CONNECTED EPISODES.
S15 E02 
Connected through Fraggle Rock thermos, Pepper Jack, Paddy’s Pub and 5 more.
S02 E02 
Connected through Garden shears, Stakeouts, Camcorders and 6 more.
S10 E10 Connected through Cookies, Mrs. Mac, Paddy’s Pub and 5 more.
S16 E01 Connected through Refrigerators, Paddy’s Pub, Frank Reynolds and 4 more.
SOURCES & NOTES.
Tags document researched occurrences, not every appearance. Read the research notes and attribution.