Gabriel Dean is an FBI Agent in Tess Gerritsen's series of novels, Rizzoli & Isles. He is also Jane Rizzoli's husband and the father of Regina.
Gabriel was first introduced in The Apprentice when he was sent by Senator Conway to oversee Jane's investigation on the Dominator and Surgeon killings. Jane first was really pissed off about the FBI Special Agent coming to take her turf, calling him a 'fibbie' and Korsak calling him 'James Fucking Bond'. But then, Gabriel was attracted to Jane and was caring about her stress about the case. Then, they both had feelings for each other and had sex.
In The Sinner, Jane was pregnant and had hesitation to tell Gabriel, but eventually, she tells Gabriel, and they ended up getting married.
Gabriel continues to assist Boston PD for cases.