M-4 Shuriken: In the "Priority: Mars" mission, it is found inside a lobby security room where Liara works at a computer. Pick up this weapon before activating the security console.

M-9 Tempest: In the "Tuchanka: Turian Platoon" mission, it is found on the ground after defeating a set of unaware Husks and climbing a ladder up, deeper into the caves.

M-25 Hornet: In the "Priority: Citadel" mission, it is found after entering a new area and taking an elevator up; look on the right side for a few items, including this weapon.

M-12 Locust: In the "Priority: Horizon" mission, it is found on the right side of the early lab.