Francis Kendrick is the Deputy of the Freeburg Police Department at the start of the game. He has recently been implicated in one of the largest corruption scandals in the city's history, although he was cleared of all charges.
Kendrick is the Sand mafia's mole in the Police Department. Early on, he will approach Jack asking him to take on his agreement with the mafia while he flees Freeburg with his family. Jack can agree or disagree with this proposal and the answer seals Kendrick's fate.
If Jack agrees to become the mafia's inside man, Kendrick flees Freeburg to start a new life elsewhere with his family. If Jack turns him down, Sand has Kendrick and his family murdered and a photo of their severed heads sent to Jack and forces him to become his inside man anyway.
The decision whether or not to help Kendrick determines the initial loyalty of the mafia. Leaving him alive also makes the assault at the end of the game easier to perform even though his involvement in it is not explained or hinted at.