Across:
1 Works out what’s wrong (CRIMINOLOGIST) by studying what constitutes a battery, for example (studying what constitutes a battery/assault = CRIMINOLOGIST),
10 Chinese neighbour (RUSSIAN) describes 33 down (RUSSIAN describes ‘Tsar’),
11 Risk taker (INSURER) is fashionable (IN-), confident (-SURE-) and right (-R) (INSURER),
12 Lots of enchiladas, for one (MEAL), with sides in Mexican capital (sides in ‘Mexican capital’ = MEAL),
13 Upstanding type (BIPED) of detective (IP = -IP-) turned over (= reversal indicator) in sleepy place (B-ED) (BIPED),
15 Commuters failing to get Metro (‘commuters’ failing to get ‘Metro’ = cmus = SCUM) from 32 down could be similar (‘film’ similar to SCUM),
17 Row (OAR) involving storyboard characters (involving ‘storyboard’ characters = OAR)
19 Local crazy guy (NUT-) promotes academic research (Royal Irish Academy = -RIA) (NUTRIA) of river rat (NUTRIA),
21 Hector (hector/jeer = -BOO-) found in bar (BA-N) (BABOON) with primate (BABOON),
22 Heartless (i) family (‘kin’ without ‘i’ = KN-) disturbed (= anagram indicator) peace (peace = -EECAP) (KNEECAP) by hanging around the joint (KNEECAP),
23 Tiny portrait lying on the chest (portrait/photo in LOCKET) as a reminder – just in case! (LOCKET = case for mementos),
25 In retrospect (= reversal indicator), left (-L) to give a hand (aid = -DIA-) in hospital (ER = RE-) (REDIAL) in Ring, again (REDIAL),
27 The great unwashed (MOB) could be from 8 down, for instance (MOB in ‘criminal class’),
29 Solomon misses son (‘Solomon’ misses ‘son’ = lomo = LOOM) working in the weaving factory (LOOM),
30 It’s handed to someone on a plate (DOYLY) for party (DO-) on Fourth of July (fourth letter of ‘July’ = -Y-) and that’s only (only) the half of it (‘only’ the half of it = -LY) (DOYLY),
31 Showroom model (DEMO) discovered in pandemonium (discovered in ‘pandemonium’ = DEMO),
34 That man (-HIS-) covered by outrageous (= anagram indicator) post (post = SOP-T) (SOPHIST) worked in old philosophy department for no good reason (SOPHIST),
35 Walter (Walter = WA-TREL) Cook (= anagram indicator) takes in Pole (South Pole = -S-) (WASTREL) – a good-for-nothing (WASTREL),
36 Someone on Twitter tweeting on Midsomer Murders perhaps (CRIME REPORTER) has a lot to say about The Killing (CRIME REPORTER).
Down:
2 Take five (REST-) from the front off (D) Dart (‘Dart’ without ‘D’ = -ART) (RESTART) and continue after a break (RESTART),
3 Fair-minded friend missing (‘fair-minded’ friend missing/without ‘friend’ = amid = MAID) in the hotel (MAID),
4 Centurions get no rest (‘centurions’ get no ‘rest’ = cnuion = NUNCIO) on papal mission (NUNCIO)
5 Strange (= anagram indicator) role – it (role it = LOITER) is what you’d expect a lounge lizard to do (LOITER),
6 Rhapsodize (GUSH) producing Mercury (Hg = G-H) retrospective (= reversal indicator) taking in all the states in America (-US-) (GUSH),
7 Teacher (SIR-) from old (-O-) college (-C-) is firm (-CO) (SIROCCO) with dry, windy type from Africa (SIROCCO),
8 Teaches parable about the thief in the night presumably (CRIMINAL CLASS) to those synonymous with sharp practice (CRIMINAL CLASS),
9 Sounds like Hell (CRIMINAL WORLD) – where everyone robs Peter to pay Paul perhaps? (CRIMINAL WORLD),
14 One of those in 18 down (PAGE- in the ‘paper’) is a little guy (-BOY) (PAGEBOY) with short haircut (PAGEBOY),
16 Enjoyed (LIKED) playing (= anagram indicator) idle (idle = LI-ED) over the weekend (‘week’ end = -K-) (LIKED),
18 Pressure (-P-) in keeping back (= reversal indicator) harvest (reap = PA-ER) (PAPER) leads to report (PAPER),
20 One of those from The Hill (ANT) involved in vigilantism (involved in ‘vigilantism’ = ANT),
21 Watering hole (BAR) containing rhubarb (containing ‘rhubarb’ = BAR),
24 Harvester (CROPPER) comes to this in failure (a CROPPER),
26 Fierce (fierce = ICE-FRE-), wild (= anagram indicator) extreme climate (extreme ‘climate’ = -E) (ICE-FREE) without frost (ICE-FREE),
27 Has potential to be a smoking gun (MORTAR gun/shell) in The House (MORTAR),
28 See Red (see red = BLOW UP) is unhappy (-LOW) in revolutionary (= reversal indicator) bar (pub = B- UP) (BLOW UP),
32 She isn’t in Flemish (‘she’ isn’t in ‘Flemish’ = flmi = FILM) picture (FILM),
33 Content of constant sarcasm (content of ‘constant sarcasm’ = TSAR) of foreign despot (TSAR).