With recent advances in genetics, many new strategies for pestcontrol have become feasible. This is the second article in which wemodel new techniques for pest control based on the mass release ofgenetically modified insects. In this article we model the release ofinsects carrying a dominant and redundant female killing or sterilizing(FK) allele on multiple genetic loci. If such insects are released intoa target population, the FK allele can become widely spread in thepopulation through the males while reducing the population eachgeneration by killing females. We allow the number of loci used to varyfrom 1 to 20. We also allow the FK allele to carry a fitness cost inmales due to the gene insertions. Using a model, we explore theeffectiveness and optimal strategies for such releases. In the mostideal circumstances (no density-dependence and released insects equalin fitness to wild ones), FK releases are several orders of magnitudemore effective than equal sized sterile male releases. For example, asingle release of 19 FK-bearing males for every two wild males, withthe released males carrying the FK allele on 10 loci, reduces thetarget population to 0.002% of no-release size. An equal sized sterilerelease reduces the target population to 5% of no-release size. Wealso show how the effectiveness of the technique decreases as thefitness cost of the FK alleles in males increases. For example, theabove mentioned release reduces the target population to 0.7% ofno-release size if each FK allele carries a fitness cost in males of5%. Adding a simple model for density-dependence and assuming thateach of the released males carries the FK allele on six loci, we showthat the release size necessary to reduce the target population to1/100 of no-release size in 10 generations of releases varies from0.44:1 to 4:1 (depending on parameter values). We also calculate theoptimal number of loci on which to put the FK allele under variouscircumstances.