Solomon Islands police are concerned at an escalation in violent crime in parts of Honiara.
In the latest incidents two expatriate couples have been attacked in their homes.
The home of missionary Kevin Rietveld was stoned and robbed on Saturday morning by 20 youths.
Mr Rietveld was hurt in the attack.
On Sunday morning 6 men invaded the home of missionaries with the Seventh Day Adventist church.
The husband was held at knifepoint while the wife was raped by three of the men.
Police commissioner, Shane Castles, says gangs of youths from the Burns Creek squatter settlement in East Honiara are responsible.
He says the attacks are mostly opportunistic.
"But the sharp escalation is a worry and we have got information that there are people ring leading this from a youth perspective and that's a concern as well. Up to this point we have arrested 12 people, 12 young me, so far, since Friday/Saturday.."