Both-- from a quick googling of the questions given to the jury in the two trials, both the questions asked and the standards of proof are different. In the murder trial, the jury needed to find “malice aforethought.”
Civil trial
[QUOTE=Judge Fujisaki]
Do you find by a preponderance of the evidence that defendant Simpson willfully and wrongfully caused the death of Ronald Goldman?
Yes or No
[/QUOTE]
Criminal trial
http://www.lectlaw.com/files/cas62.htm
[QUOTE=Judge Ito]
The defendant is accused in courts one and two of having committed the crime of murder, a violation of Penal Code Section 187. Every person who unlawfully kills a human being with malice aforethought is guilty of the
crime of murder, in violation of Section 187 of the California Penal
Code.
**
In order to prove such crime, each of the following elements must
be proved one, a human being was killed, two, the killing was unlawful,
and, three, the killing was done with malice aforethought.**
Express malice is defined as when there is manifested an intention
unlawfully to kill a human being. The mental state excuse me when it is
shown that a killing resulted from the intentional doing of an act with
express malice, no other mental state need be shown to establish the
mental state of malice aforethought. The mental state constituting
malice aforethought does not necessarily require any ill will or hatred
of the person killed. The word, ``aforethought’’ does not imply
deliberation of the lapse of considerable time. It only means that the
required mental state must precede rather than follow the act.
[/QUOTE]
[QUOTE=Judge Ito]
Reasonable doubt is defined as follows. It is not a mere possible doubt,
because everything relating to human affairs is open to some possible or
imaginary doubt. It is that state of the case which, after the entire
comparison and consideration of all the evidence, leaves the minds of the
jurors in that condition that they cannot say they feel an abiding
conviction of the truth of the charge.
[/QUOTE]