Jordan McGhee, the 17-year-old Hearts right-back, cut across Lewis Stevenson in the penalty area and brought him down when the Hibs man was not in a dangerous position eight minutes from time, and Liam Craig tucked away the penalty to give Hibs a 2-1 win in Butcher's first derby in charge of the Easter Road side. James Collins had put Hibs ahead in the second half before another Hearts youngster, David Smith, equalised.
The defeat means Hearts remain 16 points adrift of Ross County. Referee Bobby Madden got the penalty decision right but that was not how Locke saw it. "It's very difficult to take," said the Hearts manager. "We worked our socks off to get back in the game and to lose such a controversial goal is a hard one to take. I've seen it again, and Jordan goes across the lad. But the ball's already out of the pitch. You see that type of thing happening week in week out and there's never a foul given.
"Some of the decisions that we've had over the course of this season have been nothing short of incredible and I just hope our luck turns a wee bit. Yet again, we've been hit by a referee's decision that we've got to take on the chin."
Butcher, by contrast, was thrilled. "I was delighted with many aspects. We conceded a goal, which isn't like us, but I was delighted with the reaction when we did concede. There have been times in the past, looking from afar, when the boys would have let it affect them. In the past Hearts would maybe have taken a point or even gone on to win the game. But our boys steeled themselves, came back into it and thoroughly deserved to win.
"We don't get penalties. We've had one league penalty all season and it came tonight. Lewis has been challenged, [referee] Bobby Madden was very close and gave it. I'm delighted he made the decision. I think it was the right decision. There was no reason to make the challenge on Lewis, and Lewis has been wiped out.
"There was enormous pressure on Liam when he stepped up to take it, because of all the hoo-ha surrounding the decision. He stuck it away really well. We're six points behind [Inverness Caledonian Thistle] and five behind Dundee United, who we play on Sunday."
Even Hearts' Ryan Stevenson admitted it was a penalty. "If it was us I'd be saying it was a penalty," said the forward. "It's just inexperience from Jordon. You need to keep in mind the situation we're in, Jordon has just turned 17. He is a boy with a massive future in the game. Everyone makes mistakes. He was sitting in the dressing room absolutely devastated."