Watch Lethal Weapon 4 (1998) HD Full Movie Free on SolarMovie. Watch Lethal Weapon 4 (1998) online free. With personal crises and age weighing in on them, LAPD officers Riggs and Murtaugh must contend with...With personal crises and age weighing in on them, LAPD officers Riggs and Murtaugh must contend with deadly Chinese triads that are trying to free their former leaders out of prison and onto American soil.