Resigning?
The guy spent 15 months in jail. A resignation is clearly not sufficient.
No, resignation is not enough.* I don’t know the law in Texas. In other states he could be charged on felony charges. Battery is the least of what he did. False imprisonment, falsifying official reports, something analogous to perjury, a buffet of civil rights violations.
There has to be the -will- to exercise that prosecutorial discretion.
*Although if I was offered 1,100,000 to sit in jail for 15 months, I think I’d jump at it; but that does not answer the -criminal- malfeasance of the cop.