I want to reducem my if statements in my 2Dnumpy code

I have a 2D symmetric matrix (M) that contains 0,1,2

[[1. 2. 0. 0.]
[2. 1. 2. 0.]
[0. 2. 1. 2.] 
[0. 0. 2. 1.]]

I want to examin that: set atom i,j in M to 0 where j in i+1, i+2, i+3 to zero in M

I have this code, that do this:

for i in range(len(M)):
     for j in range(len(M)):
        if M[i, j] != 0:
            if j == len(M) - 3:
                M[i, j+2] = 0
                M[i, j+1] = 0
            elif j == len(M) - 2:
                M[i, j+1] = 0
            elif j == len(M) - 1:
                   continue
            else:
                M[i, j + 3] = 0
                M[i, j + 2] = 0
                M[i, j + 1] = 0
        else:
            continue

It works pretty well, but i want to reduce my if statements. I read about M[i,j:j+3], but i dont really know how to use it.

I'm waiting the following output matrix:

[[1. 0. 0. 0.]
 [2. 0. 0. 0.]
 [0. 2. 0. 0.]
 [0. 0. 2. 0.]]

Thank you for your help.