The secret services were surely involved in the murders of Falcone and Borsellino. At the Capaci massacre (where Falcone died) there was an airplane surveiling the zone that was suspected to belong to the secret service, which is confirmed by Riina in this statement:
https://www.youtube.com/watch?v=Ez2UhELuzsk
Riina also says that the mafia contact with the secret service was Antonino Gioe' who was then "suicided" in prison.

Also, there was a secret service base near the place Borsellino was killed which was then quickly dismantled.

The Addaura attempt on Falcone's life was also alleged to have taken place with the help of secret service. There have been 2 policemen, Antonino Agostino and Emanuele Piazza, allegedly involved in preventing it. They were later killed, and a secret service agent Giovanni Aiello (nicknamed "monster face") was involved in Agostino's murder; he was only identified relatively recently.

Willie Marfeo to Henry Tameleo:

1) "You people want a loaf of bread and you throw the crumbs back. Well, fuck you. I ain't closing down."

2) "Get out of here, old man. Go tell Raymond to go shit in his hat. We're not giving you anything."