This study investigates the co-channel interference effects on the leakage rate based untrustworthy relay selection strategies. The investigation considers half-duplex, full-duplex, and hybrid leakage rate-based untrustworthy relay selection strategies. The hybrid-based selection strategy dynamically switches between half-duplex and full-duplex modes. The investigation also considers a dual-hop untrustworthy amplify-and-forward based half/full-duplex bi-directional wireless relaying network in the system model. In addition, a finite number of friendly jammers and co-channel interference affect to the untrustworthy relay terminals. According to analytical, asymptotic, and Monte-Carlo simulation results, the co-channel interference slightly degrades the outage probability performance curves and causes system coding gain losses in high signal-to-noise ratio regimes. Results also show that the co-channel interference degrades the system achievable rate performance and causes additional system coding gain losses in high SNR regimes. Results also show that co-channel interference does not have any effect on the system security trade-off performance.