whoa, the Finnish version is weirdly off then lol. here's what mine has: 
Long ago, the great king Mufasa had been killed by the treacherous act of his own brother, Scar. Scar had led a renegade grop of lions who tried to seize control of the Pride Lands.
His plot had failed, and Mufasa's son, Simba, had teaken his rightful place as king.
Now Scar was dead, but his lioness Zira had not lost her thirst for power...at any cost.
Zira and the other Outsiders lived in the Outlands, a dry and barren place where Mufasa had banished them when they began making trouble. Now, Zira was plotting to avenge Scar's death. She was training her son Kovu to take Simba's place as king of the Pride Lands. She was bringing up Kovu to be strong and ruthless.
....
Under Zira's plan, everyone had a role to play. Her favorite child, Kovu, would be king. Nuka and Vitani were to protect him.
that's why I don't think Zira killed Kopa. plus that's why Simba said "My father's law will prevail." to Zira when they discovered Kiara and Kovu.
oh, and Maisha had a pic with that Scar + Nala = Vitani thing too. although, you do have to wonder how Nala knew who Vitani was during that battle. since she left for help when she was a newborn, if Zira had even had them then. and when she came back with Simba, they were banished. so how would she knew her name and what she looks like?