True, and it also preserved life, which seems to be the higher law of God...
Yes, breaking of the 9th commandment, slandering someone, seems to have the death penalty or being made an outcast.
It is a VERY serious sin in God's sight.
Proverbs 19:5 A false witness shall not be unpunished, and he that speaketh lies shall not escape.
Proverbs 19:9 A false witness shall not be unpunished, and he that speaketh lies shall perish.
Proverbs 6
16 These six things doth the LORD hate: yea, seven are an abomination unto him:
17 A proud look, a lying tongue, and hands that shed innocent blood,
18 An heart that deviseth wicked imaginations, feet that be swift in running to mischief,
19 A false witness that speaketh lies, and he that soweth discord among brethren.
Psalm 101:5 Whoso privily slandereth his neighbour, him will I cut off: him that hath an high look and a proud heart will not I suffer.