Paul Warne condemned an “embarrassing” and “completely unacceptable” missile-throwing incident that marred Rotherham’s 2-0 victory at Crewe which sent them back to the top of League One.
The Millers had top-scorer Michael Smith on target in either half against the lowly Railwaymen, who had Scott Robertson sent off in a second half.
There was a lengthy delay when a linesman was hit by a coin which appeared to have been thrown from the away fans section at Gresty Road.
There was a second break in the game as the linesman was replaced by the fourth official after complaining of “dizziness”.
“It’s embarrassing and it is completely unacceptable. If it was one of our fans and it has been seen by CCTV then the culprit should be punished,” said Warne.
“I apologised to the four officials and our captain [Richard Wood] went over as well as to see that he was all right too.
“It’s a concern for me as a human being. If that was one of my fans that is found to have done that then they should be punished.”
The club later issued a statement, which read: “Rotherham United are very disappointed to have learned of an incident involving an alleged missile being thrown at an official during our Sky Bet League One encounter with Crewe Alexandra on Saturday.
“Having discussed the matter with colleagues at Crewe, reports suggest that a member of the away crowd has been guilty of throwing a missile towards the referee’s assistant which resulted in the affected official having to be replaced on the touchline.
“The club will now investigate the matter with the help of our colleagues at Crewe Alexandra, and will look to identify and punish the individual in question.
“We are embarrassed to once again be releasing a statement regarding the behaviour of a small minority of our supporters, who are not representative of the majority, or of us as a football club.”
Rotherham moved back to the top of the table, one point above Wigan.
Warne added: “It was a massive three points as this is not an easy place to come. Crewe came at us with the wind behind them in the second half but we managed the game really well.
“The sending off had a big part to play as we scored from the free-kick. I’m pleased with the clean sheet and it is a win away from home.”
Crewe boss David Artell was busy in the transfer window finalising four deals at the end of the week, although only former Fortuna Sittard striker Bassala Sambou, who came off the bench late on, was signed in time to feature.
Artell said: “We gave the league leaders two goals and our game management wasn’t good enough.
“I thought Scott Robertson was unfortunate for the first yellow card and I didn’t see the second one [foul]. But the sending-off turned the game in their favour. We let them have a tap-in from the free-kick. We made some poor decisions that handed them both their goals.
“At 1-0 down we were still in it as they had no other chances in the first half for all their territorial dominance.
“We’ve got to do much better. Every game is important now and we’ve got to go to Gillingham on Tuesday and win the game.”