CHARLESTON, S.C. (AP) — Supporters of former New York City Mayor Mike Bloomberg are escalating their attacks on Bernie Sanders over his record on gun control ahead of Tuesday night’s high-stakes Democratic debate in South Carolina. Five Bloomberg backers, all of them current or former black officials, are homing in on Sanders’ record on guns and criminal justice as particular areas of concern. As the Vermont senator becomes the front-runner in the Democratic presidential primary, the Bloomberg backers say, more scrutiny should be paid to his past votes against the landmark gun control law known as the Brady Bill and his opposition to legislation that would allow gun manufacturers to be sued.