Thank you to IMDB user, "chipe" for composing this information--August 24, 2008.
"In the early seasons they often had episodes with clues and facts about the Trudy murder, but then there were less and less such episodes. Look at what I put together. Note the episode numbers.
We know these things about the Trudy murder. Corrections and additions are appreciated:
1. In "Mr. Monk and the Candidate" (episodes 1 and 2 -- the pilot episodes, original air date, July 2002), when Monk is reviewing the press clippings and file of the Trudy car bomb murder, there is one clipping with the intriguing headline: "No links to other car bombing suspected .. ... .." That has to be significant.
2. In "Mr Monk Meets Dale the Whale," (ep. 4, July 2002), we learn that because Trudy was doing newspaper stories about Dale's finances, Dale sued Trudy and her paper. He knew he couldn't win the law suit, but he pursued it for spite and to cost Trudy and the paper a lot of money in legal bills. This hurt the Monks: they had to sell their home, which Dale bought and turned into a porn storage site.
3. In "Mr. Monk and the Billionaire Mugger," (episode 7, August 2002) we learn two interesting things: (1) the last entry in Trudy's appointment book was "530 Kelly Street, re: Mr. Simon." Monk suddenly realizes it is not an address, but a 5:30 appointment to see a woman named Kelly (Katrina) Street. When he meets her he further learns, from her, that Mr. Simon is her stuffed pet dog. Monk is told that Trudy was probably writing a human interest story about the stuffed dead pet (Trudy was a newspaper columnist); and (2) Monk had been to the Street house about the same thing each year after Trudy was murdered four years ago, he is told! Ms. Street suggests that Monk write it down so he won't forget it. .... ..... ....(Maybe she is lying about all of this.)
4. In "Mr. Monk and the Three Pies" ( 24, Jan 2004) we learn that Monk's brother Ambrose feels "guilty" about Trudy's death and keeps his distance (due to guilt) from Monk because he sent Trudy on the errand [to get medicine] that took her to the guarage where her car blew up, killing her.
5. In "Mr. Monk Goes to Jail" (29, Mar 2004) we learn from Dale the Whale that Warrick Tennyson was in on Trudy's murder. Dale doesn't know (or won't tell) why she was murdered, but he emphatically says the bomb was intended for her and not Monk.
6. In "Mr. Monk Takes Manhattan" (30, Jun 2004) (which is the episode that follows the "Mr Monk Goes to Jail" ep.) Tennyson, as he is dying, reveals to Monk that he built the bomb that killed Trudy, that he was paid $2000 cash, that the car bomb was made of 10 pounds of plastique, magnesium charged, detonated by cell phone.. He doesn't know the name of the man who hired him and never saw his face, but remembers one detail: the man had six fingers on his right hand. (Oddly, in the USA network web site synopsis of the episode, they say the man who hired Tennyson to build the bomb was named "Frank," but in the TV show and DVD, Tennyson just tells Monk that the guy who hired him was a "freak" (because of the six fingers). The name "Frank" is never mentioned. Even the captions give the word "freak.")
7. In "Mr. Monk and the Blackout," (32, Jul 2004) a 90s anti-military radical bomber, Winston Brenner, who was thought dead, but was currently going by an alias, Gene Edelson, planted a bomb similar to the one that killed Trudy (both used plastique and magnesium, but the one in this episode used an egg timer detonator, not a cell phone). Anyway, Monk casually mentioned that he knew of Brenner because Trudy had written an article about him. At the end of the episode, Brenner gets caught and imprisoned.
8. In "Mr. Monk vs. the Cobra," (40, Jan 2005) Natalie finally persuades Monk to close up (stop paying rent on) Trudy's old office. I don't know what might be in the contents and where they are now.
9. In "Mr. Monk and Mrs. Monk," (51, Aug 2005) we learn that Trudy was an investigative reporter for a newspaper. There she worked on a blockbuster story involving union corruption. An anonymous union insider had given her information that put a lot of union officials in jail. The insider then became head of the union, but he became afraid (after Trudy died) that information that she kept in a storage locker of Trudy and writing partner, recently deceased (how?) Janice Ellinghouse, would become public and reveal his part in the story. While trying to destroy this evidence by setting a fire to it, he was killed by the police.
10. In "Mr. Monk and the Man Who Shot Santa" (87, Dec 2007) they again made reference again to the fact that Monk never opened Trudy's Christmas gift to Monk. It was wrapped in holiday paper. Monk has no idea what is inside it. It has been 10 years since Trudy was murdered. Crime never solved; it haunts Monk. Maybe there is a clue inside the package that will solve the crime!
11. In "Mr. Monk Is On the Run, Parts I and II) (92 and 93, Feb 2008) Monk learns from letters found in Frank Nunn's (the 6-fingered man's) apartment that someone called just "The Judge" had hired Nunn to plant the bomb that killed Trudy. These two episodes had two Dale the Whale plots going on at the same time: (1) Dale hired Nunn to plant a bomb intended to kill the Governor (who turned down Dale's prison pardon request) so the Lieutenant Governor would become Governor and pardon Dale; and (2) Dale had Nunn killed, and at the same time arranged to have Monk framed for Nunn's murder, thus sending Monk to prison (revenge for Dale who had been put in prison due to Monk's detective work). ... ... .... To refresh everyone's memory at this point: The Judge (whoever he is) hired Frank Nunn (the 6-fingered man) to plant the bomb which killed Trudy after Nunn had hired Warrick Tennyson to make the bomb. Both Nunn and Tennyson are now dead.
12. In "Mr. Monk and the Genius (July 2008 - Season 7, Episode 2), Monk mentions that he barely made it to Trudy's side before she died. She could not speak, but held on to both of his hands until she died. The victim, the wife of the Genius, hired Monk to solve her murder. He swears to do so, as she holds both of his hands the same way Trudy did. Monk gives this reason to Stottlemeyer for not walking away from the case.
The case was finally solved in the 2 part series finale Mr. Monk and the End
(Incidentally, be sure to see this great site (I have no connection to it) devoted solely to Trudy: http://www.eviltwinltd.com/trudy.htm )"