Pro Publica writes about the Liberian civil war:
Taylor commanded a pauper’s army that grew to thousands, led by a handful of trusted lieutenants, Libyan-trained mercenaries and professional military men.
Among the most notorious recruits were the Small Boys Unit — young children, often orphans, who swore allegiance to “Papai,” as Taylor was called. To prove their loyalty, the children sometimes had to gun down their mothers and fathers. They would become among some of the most vicious killers in a war of heartless, mindless, unfathomable killing.
Pro Publica is a fairly reliable source, but still one has to wonder the level of implausibility that children were required to do this, that is kill their parents.
A similar claim is found in a Child Soldiers International's, Child Soldiers Global Report 2001 - Liberia, but the source and evidence is again somewhat vague.
Many were forcibly recruited and forced to rape, torture or kill fellow villagers or even relatives in order to instil loyalty. [cited to Beauchemin, E., "Child soldiers in Liberia", Radio Netherlands.]
What level of evidence exists for the highlighted claim?
(Somewhat of an side, Taylor was judged and found guilty at the Hague for war crimes committed in neighboring Sierra Leone. The proceedings however followed a novel “notice pleading” format and avoided Milosevic-trial-style level of detail, so the charges were only generally outlined, which isn't helping answer this particular question.)