Cryptic crossword No 3,635

Across

1. Gawp at twisting stab finishing off girl close to college (4)
2. Madly insatiable gossip (10)
3. Antiquated old boy, last of thuggee, strangling single traveller at first (8)
4. Unlucky Oscar gets shot in the head outside (6)
5. Embrace conceals end of dagger causing a sharp intake of breath (4)
6. Fiery spirit clutches dad having lost son (6)
7. Bride at centre of festivity battered in bitter attack (8)
8. Shooter runs as long as race finishes early (8)
9. Uncle gets shot after decapitation fails (8)
10. After rolling Grant over, you cut belly and tongue (6)
11. Overwhelming work by reporters beginning to investigate Vatican City crime at last (10)
12. Witness oddly "disappeared" just seconds from Sittingbourne Strangler's guilt being established (2,4)
13. High-pressure tank blast essentially encore testimonial of exiting professor (3,10)

Down

1. Endless shame! Representative about to stab Caesar and others (8)
2. Wait around outside of launderette - that's how Hannibal Lecter found his victims (6)
3. Writer served up, cannibal finally ate! (4)
4. Torn by grave message over police erasing data initially (6)
5. Fellow bled internally, tissues drained, tip of épée having cut many, many vessels (6)
6. Murder that is cold-hearted! (3)
7. Ending for many Russian women in cells (3)
8. Botched job by executioner initially leading to court challenge (6)
9. Chop up body with a dagger, essentially placed next to head from graveyard, in vessel for carrying remains (5,3)
10. Guerrilla republic's army tie infidels' severed heads on the house (6)
11. Gets killed, perhaps when guarding private sector get-togethers (6,7)
12. Sinister character leaving in disguise, wearing somebody's face (8)
13. After offing Earl, organised criminal reaches dead end, for example (4,4)
14. John Paul II possibly stabbed by a ringleader in prison break? (6)
15. Similar suspicions of someone unhinged choking humans (4)