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 intricate quest. First you must have a permission to speak with the head of the Wright family, Orville Wright. For that ask Keith Wright about work and pass a Speech check (impossible if you're Berserker, Childkiller or have -101 Karma).

Speak to Orville and offer to do the job for him, and he'll tell you 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.

ALTERNATIVE: From this point on, speaking to Orville and accusing any known suspects accomplishes the quest (Reward: 500 XP, $250, 2 Booze and 20 Shotgun shells), but there's much more to it.

Talk to Keith and ask for permission to investigate Richard's room (needs INT of at least 7). Inspect one of the bookcases to find an empty jet canister (Reward: 500 XP).

Talk with Jagged Jimmy J, let him examine the empty jet canister. He'll tell you the jet left inside has traces of radscorpion venom in it (Reward: 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 (Reward: 1000 XP). This will, however, make you a "grave digger", and mentioning this little tidbit to Orville will not please him.

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 (Reward: 1000 XP).

Finally, return to Orville Wright and tell that Richard was actually poisoned and that Renesco was hired by the Salvatores to make the poisoned Jet (Reward: 500 XP, $250, 2 Booze and 20 Shotgun shells) to have him declared a dead man by Orville, then correct him and explain that Salvatores did it, likely to provoke a war between the Wrights and the Mordinos (Requires INT of at least 7 and knowledge of all families to reveal the true motive. Reward: 2000 XP, $350, 2 Booze and 40 Shotgun shells). Mentioning Renesco's involvement and then successfully revealing Salvadores' motive keeps Renesco alive, but it is possible to omit mentioning Renesco altogether for exchange of not receiving the appropriate reward.

The maximum combined XP rewards for this quest is 4500.