Hell no 13 hands isn't enough. 13 hands is nothing. It's not even two orbits.
You can only begin to form a vague outline of a suspicion at that point. It could go either way - hot card streak or just a loose player.
That early on, without extraordinary indicators, you just have to pay attention and play ABC poker against them.
What's extraordinary? Well, not playing less hands. But playing more... here are two anecdotal examples for you.
1st example Live table, $1/3,
New player arrives at table with fairly short stack ($100). Table has been loose passive, and the occasional single raises get 4-5 callers. New player comes in at late position, it limps around to him, and he shoves. Table folds. New player has boosted his stack by 20-30%. Good play, right?
Well, next hand, someone raises, and he 3-bets big. Again, he takes it down. Hand after hand, with only 1 or two folds, he continues playing VERY aggressively, and the table has got him, because he's not playing 5 out of 13, he's playing 7 hands out of 10. NOBODY has it that good that often.
So people start calling his shoves with hands that, to anyone else, they'd fold. I happen to be the first - calling his all in shove with my own JJ. IIRC he had two suited unders (1 gappers I think), and I draw first blood. 2-3 rebuys later, he's gone. He was completely obviously a maniac and nobody missed that.
2nd example - bit more involved.
One player is playing a fairly wide range - 50-60% of hands, and calling down pretty bad showdown cards like bottom pair worse kicker cards on broadway card heavy boards. First time I see him do this, the very next hand, it limps around to him, there's about $12 in the pot, and he shoves $140 or so. Of course, he takes it down.
A bit later, he plays another horrible hand into the ground, and again, very next hand, this time with $3 in the pot, he shoves $90. He does this a 3rd time, shoving huge after losing a moderate pot he should have let go early, and takes it down again.
Of course, he does win some smaller pots too, but then he loses another moderate one, and I know, with absolute certainty, exactly what is going to happen next.
He's in the BB, I'm in CO. HJ limps, I have A8o, so I decide yep, this is the moemnt, and I limp, BTN limps, SB limps, BB SHOVES, $85. Now I've not built up much of a stack yet, I started with $300 and I'm up about $60 and HJ folds. Now if HJ had called, I'd have folded, but HJ folded, and I know it's only gonna put me down $20 from my BI if I DO lose, so I flat call. BTN and SB fold (and later tell me that if I had folded, then BTN would have called and if BTN had folded, SB would have called, so we all knew what was going on)...
Anyway, I called an $80 shove into a $10 pot with A8o. Horrible, right? Except that BB had 57o, and we both missed the board, but even if he'd caught, my read was correct, I was ahead to begin with, and I was right that the other two would fold if I called. Something of a gamble, of course, but poker IS something of a gamble.
The point is even if I'd lost, I was paying attention to the player, and knew what he was going to do, and the odds were vastly against him having a monster hand EVERY TIME immediately after he lost a pot by being an idiot.
In the end, he lost about a grand. He lost his stack to me about 4 times, and only one won all in against me, when his AQ vs my AK caught a river Q.