The FBI offered a $5,000 reward Tuesday for help finding whoever mailed dozens of threatening letters — including some containing a potentially harmful insecticide — complaining about TV coverage of college cheerleaders and professional female athletes.

The writer or writers complained that ESPN and ABC crews have exploited cheerleaders, WNBA players and WTA Tour players through certain camera angles, even though those angles were rarely shown on the air.

The FBI released excerpts of two letters in the hope of identifying who sent them.

"For the past 6-7 years, ESPN and its nationwide networks have exploited cheer/dance teams all across the country. They do this by parking their TV cameras on these women for their own personal entertainment," an excerpt from one letter said.

"Pigs park their cameras on us close up, front view, dozens of times each game, yet rarely ever show on TV in this manner," another excerpt read.

Investigators believe the author "may be directly or indirectly involved in some element of cheerleading and/or the television production/coverage aspect of collegiate athletics," according to an FBI statement.

A spokesman for ESPN said the network is cooperating with authorities but could not give details about the investigation.

The letters were sent to national networks and their local affiliates, as well as people in states throughout the West and Midwest, according to the FBI office in Portland. Recipients also included people associated with university athletic departments in Ohio, Michigan and Arizona.

The initial batch of letters was postmarked in Portland and delivered in September 2004. Subsequent batches of letters were delivered between November 2006 and February, mostly with postmarks from Seattle, but some also were sent from Chicago, the FBI said.

The letters claim camera crews spent too much time on close-ups of cheerleaders. One letter also complained about coverage of WNBA players.

The FBI declined to identify the kind of insecticide contained in some of the letters but said there were no reports of injuries.

In a letter sent in September 2004, the author objects to the timing and angles of the shots captured by camera crews during sports events.

"We have asked nicely for them to respect us and all women, yet they refuse. They exploit innocent people, so we will too. When they start respecting us, we stop mailing these out," the letter reads.

The author of a letter sent in December 2006 complains that networks unfairly favor more modestly dressed cheerleading squads.

"For the last 6 years, Ohio State cheerleaders have received more TV time than any other Division 1A cheer squad on ESPN, because they wear long sleeved red/white outfits. If they wore sleeveless outfits, they would not get ANY TV time. So, we are fed up with this constant exploitation," the author wrote.

Calls made after hours Tuesday to Ohio State officials, WNBA headquarters and a WTA Tour spokesman were not immediately returned.