There have been aerial signs reading “Hillary for Prison,” rallying cries of “lock her up,” misogynistic souvenir swag mocking her body parts and, in a violent turn, a public call for Hillary Clinton to be executed.

Political conventions are usually a mix of talking up the party’s nominee and denouncing the opponent. But as Republicans gather in Cleveland to nominate Donald J. Trump, the venom being directed at Mrs. Clinton, the presumptive Democratic nominee, has taken a strikingly sinister tone that makes the days of Swift-boating and Bush-bashing at past conventions seem tame.

Here are some of the harshest attacks leveled at Mrs. Clinton this week.

Firing Squad or Electric Chair?

Hillary Clinton’s responsibility for the deaths of Americans in Benghazi, Libya, in 2012 has been a regular topic of conversation among Republicans, and on Tuesday Al Baldasaro, a delegate for Mr. Trump from New Hampshire who advises him on veterans issues, suggested that she had committed treason.

“This whole thing disgusts me — Hillary Clinton should be put in the firing line and shot for treason,” Mr. Baldasaro said on The Kuhner Report radio show.