Find out who was responsible for Richard Wright's overdose

Find out who was responsible for Richard Wright's overdose is a side quest in Fallout 2.

Walkthrough
This is quite a long and a bit complicated quest. First you must have permission to speak with the head of the Wright family, Orville Wright. Offer to do the job for him for free, and he'll tell the player to find out who killed his son Richard by "forcing" a Jet overdose on him. Orville names Jules, Jagged Jimmy J, Renesco and the Mordinos as suspects.

From this point on, talking with any of the suspects and then returning to the Wrights accomplishes the quest, but there's much more to do. Talk to Keith outside Orville's room and ask for permission to investigate Richard's room (Your characters INT has to be at least 7). Inspect one of the bookcases to find an empty Jet canister. This earns the player 500 xp.

Talk with Jagged Jimmy J, ask him about Richard, then have him examine the empty Jet canister. He'll tell you the Jet left inside has traces of radscorpion venom in it. This discovery earns the player 500 xp. Alternatively, if you were unable to search Richard's room for the canister, you can dig up his grave at Golgotha where your character, after observing the site, will notice a smell that can be attributed to radscorpion poison. This will, however, earn you the perk "grave digger", and mentioning this little tidbit to Orville Wright will cause him to attack you.

Talk to Renesco, and mention the poisoned Jet. He will remember the Salvatores coming to him one day and having him poison some Jet for them. This gets the player 1000 xp.

Finally, return to Orville Wright and tell him "Renesco was hired by the Salvatores...." to have him declare Renesco a dead man, then correct him and explain that Salvatores did it, likely to provoke a war between the Wrights and the Mordinos. This earns the player some items, 500 xp for mentioning Renesco, and 2000 xp for revealing the true culprit.

The combined xp rewards for this quest is 4500 xp. The player can also leave out Renesco's involvement, and will not receive xp for mentioning it appropriately. Fingering anyone else besides the Salvatores (Renesco included) as the culprit earns the player 500 xp. Ultimately, it's worth the extra time to investigate and get more xp.

Orville tells the player not to kill the culprit if they find him. Thus, if the player kills Jagged Jimmy J, Renesco or Jules, and tells Orville they were the culprit, he will attack them once they report back, though the player still gets xp. The player can, however, kill the Salvatores and finger them without being attacked. Anyone besides the Salvatores the player names as the culprit vanish, probably killed by the Wrights, so try to avoid accusing Renesco if you plan on buying from him again.