Differences between criminal and civil law

OJ Simpson was tried in criminal court in California for the 1994 murder of his ex-wife, Nicole Brown Simpson, and her friend Ronald Goldman. After a lengthy criminal trial, in 1995 the jury found OJ Simpson not guilty, and he was acquitted of the crime.

In 1997, the parents of Ronald Goldman brought a civil suit against OJ Simpson for wrongful death, and despite OJ Simpson's acquittal in the criminal case, the jury found OJ Simpson responsible for the death of Ronald Goldman and awarded the plaintiffs (Goldman family) compensatory and punitive damages of $33.5 million.

Why were the Goldmans permitted to sue OJ Simpson for wrongful death in civil court after he was acquitted of the criminal charges?

Thinking about the differences between criminal and civil cases in the materials, why would a jury find OJ Simpson responsible for Ronald Goldman's death when the jury in the criminal case found him not guilty?

If the plaintiff's lawyers in the civil case had presented additional evidence proving that OJ Simpson had committed the murders, why was he not ordered to be incarcerated? Could he have been retried on criminal charges?

300 word minimum discussion.